Talk:Manchester Mark 1

Question

April 1954 or 1949?

The article said "The first version of the machine was running in April 1954". The book "Early Britis Computers", page 37 says that it was used to investigate Mersenne primes in April 1949. It ran overnight in June 1949, and that it was completed in October 1949.--Bubba73 16:22, 4 Jun 2005 (UTC)

Mark I coincidence

Is it by pure coincidence that this machine shares a similar name to Harvard Mark I? --Abdull 10:17, 11 March 2007 (UTC)

Yes, unrelated. However, the Baby Mark 1, Ferranti Mark 1 and intermediary version of the Manchester Mark 1 where all known as the "Mark 1" despite being different evolutions of the same machines. This link has something to say on the matter. --BlueNovember 00:01, 12 November 2007 (UTC)

Size of a page

I'm confused by this text:

The Mark I included two tubes, each storing 64 rows ("double density") of 40 points, for a total of 128 words. 64 words was considered to be a single "page", so the system stored 4 pages. Freddie Williams deliberately sized the drum to store two "pages" of Williams tube data – that is, 2x32x40 = 2,560 bits – per track, and 32 tracks in total.

The word size is 40 bits. Each tube stores 64 words. There are two tubes. 64×2 = 128. This makes sense. Then it says there were four pages. How exactly does 64×4 = 128? Did I miss something? Apparently two pages of data is 2×32 words... so presumably the article should say '32 words was considered to be a single "page"'? --StuartBrady (Talk) 19:08, 11 September 2007 (UTC)

Re-name the article?

Can the article name be corrected from "Mark I" to "Mark 1"? TedColes (talk) 18:19, 1 December 2008 (UTC)

I'd certainly be in favour of that. There's a redirect from Manchester Mark 1 to here though, so I'm not sure whether that means the move's got to be done by an administrator? --Malleus Fatuorum 18:23, 1 December 2008 (UTC)

I'm in favour of changing it as it's not consistent with the text but it will need to be done by an admin as the name's already in use. Richerman (talk) 11:48, 2 December 2008 (UTC)

Met Office thing

http://www.computer50.org/mark1/gac1.html states that it was the Ferranti mark one that was used by the met office, not the manchester mark one, —Preceding unsigned comment added by Steroberts89 (talk • contribs) 00:35, 16 January 2009 (UTC)

Fixed Y Richerman (talk) 12:35, 16 January 2009 (UTC)

Berners-Lee/Mark 1 confusion

I've removed the claim that Tim Berners-Lee's Dad, Conway Berners-Lee, worked on the Manchester Mark 1. He actually worked on the Ferranti Mark 1.[1] --Malleus Fatuorum 20:11, 22 January 2009 (UTC)

Well done

Superb - well written and comprehensive.
I added a few links, such as word and page

Any point in putting the translation table in so people can see how the info changes through the process?
eg

INPUT	Z	D	S	L	Z	W	R	F
TELETYPE	10001	10010	10100	01001	10001	11001	01010	10110
MARK 1	10001	01001	00101	10010	10011	10011	01010	01101

I know that looks ugly but was just as an example !--Chaosdruid (talk) 18:28, 25 January 2009 (UTC)

PS - just added link to Mark 1 in the Mersenne prime page

I'm not sure. The article does already say that the Mark 1 reversed the conventional ordering of significant digits ... I was tempted at one point to include a table of the complete mapping of teleprinter codes to binary values, but thought better of it. It's very difficult writing encyclopedia articles, rather than articles about some topic or other, and I've certainly struggled with that in the past. My take on it is that we're trying to give a comprehensive summary, not a comprehensive account, if that makes any sense. --Malleus Fatuorum 18:49, 25 January 2009 (UTC)

Yup makes perfect sense - it is difficult to know where to draw the line between essay and article for me lol--Chaosdruid (talk) 22:15, 25 January 2009 (UTC)

GA Review

This review is transcluded from Talk:Manchester Mark 1/GA1. The edit link for this section can be used to add comments to the review.

Hi, I'll be reviewing this article. The rules for GA reviews are stated at Good Article criteria (OK, Malleus knows these perfectly well, but this is for the benefit of others).

I usually do reviews in the order: coverage; structure; detailed walk-through of sections (refs, prose, other details); images (after the text content is stable); lead (ditto). Feel free to respond to my comments under each one, and please sign each response, so that it's clear who said what.

When an issue is resolved, I'll mark it with  Done. If I think an issue remains unresolved after responses / changes by the editor(s), I'll mark it  Not done. Occasionally I decide one of my comments is off-target, and strike it out --Philcha (talk) 16:09, 8 February 2009 (UTC)

Coverage

I think there are significant gaps here from the point of view of a non-specialist reader - or even a techie with no knowledge of the history. A lot of it's what was not present in the Mark 1, to make it plain what a primitive stage in the development of computers this was:

• A summary of relevant parts of History of computing hardware would help provide context, e.g.: EDVAC was the first stored-program computer designed (proposed August 1944) but only went live in 1951; SSEM was the first one to go live (June 1948); EDSAC live May 1949, 5 months before Mark 1. -Philcha (talk) 16:09, 8 February 2009 (UTC)
• The Manchester Mark 1 started work in April 1949, the month before EDSAC started work. Neither machine was complete on those dates. The Manchester Mark 1 was completed in October 1949. EDSAC was slower to be completed and had a less advanced architecture: it didn't get its full main store until 1955/56, didn't get index registers until 1953, and never got a backing store.
• Should mention that there was no OS, which everyone has taken for granted since the mid-1950s (GM-NAA I/O may have been the start, in 1956, but was only a job queue manager; proper "I am God" OSs only appeared live in the 1960s). --Philcha (talk) 16:09, 8 February 2009 (UTC)
• Atlas Supervisor counts as the first OS according to some. The first Atlas was commissioned in 1962.
• Presumably there was not even an assembler, and the Mark 1 had to be programmed in binary or the compressed representation of binary the article quotes ("ZDSLZWRF")? --Philcha (talk) 16:09, 8 February 2009 (UTC)
• Yes, but: they developed a "relatively high level language" for the Ferranti Mark 1 by 1952. Mark_1_Autocode http://www.computer50.org/mark1/program.html — Preceding unsigned comment added by 86.141.217.115 (talk) 02:49, 28 January 2014 (UTC)
• Did it have any built-in interrupt handling? I'd guess it relied on clock synchronisation of CPU and memory / drum operations, but what about paper tape I/O? Looks like the first hardware-based interrupt handler may have been around 1957, see e.g. John McCarthy's REMINISCENCES ON THE HISTORY OF TIME SHARING (look for "IBM 704"). --Philcha (talk) 16:09, 8 February 2009 (UTC)
• IIRC IBM's licensing of index registers and other Manchester techs was what enabled it to overtake the early commercial leader Univac in the mid-1950s. I.e. the Mark 1 was a significant factor in the rise of "Big Blue". If that can be supported, it's historically important. --Philcha (talk) 16:09, 8 February 2009 (UTC)
• Should disambig from Harvard Mark I, often known as "Mark I" in the literature. --Philcha (talk) 22:51, 8 February 2009 (UTC)
  • This article is called the "Manchester Mark 1", not the "Mark 1". No disambiguation is necessary. --Malleus Fatuorum 23:02, 9 February 2009 (UTC)
• Several of the sources I've found say that Eckert & Mauchly: were so overwhelmed by requests for info about ENIAC that they ran a summer school at the Moore School, and the Manchester team got a lot of ideas there; E & M first raised the idea of a stored program computer, but their notes dealt mainly with the engineering issues and von Neumann's more elegant abstract presentation got more attention (and he had more political pull, being in on other programs such as the A-bomb). --Philcha (talk)

I'll deal with structure when coverage issues are resolved. --Philcha (talk) 16:09, 8 February 2009 (UTC)

• Replies

Thanks for undertaking this review. I'll try to deal with the issues you've raised:

• The National Physical Laboratory's Pilot ACE, Cambridge University's EDSAC, and the US Army's EDVAC are already mentioned in the first paragraph of the Background section. Anyone who wants more history can click on the hat to the History of computing hardware.

• I've explained what system software was available, and that there was no operating system. --Malleus Fatuorum 19:18, 8 February 2009 (UTC)

• There was no assembler, the machine was programmed in binary, as you say. I've added a sentence to make that clear. --Malleus Fatuorum 18:48, 8 February 2009 (UTC)

• There was no interrupt system. As you suggested, the rotational speed of the drum was chosen to synchronise with the CPU clock, and the machine waited for paper tape operations to complete. Again, I've added a piece to make that clear. --Malleus Fatuorum 18:48, 8 February 2009 (UTC)

• I'm not aware of any evidence that index registers or any other of the Manchester licensed technology was as crucial to IBM's success as you're suggesting. Index registers just make it more convenient to iterate through a block of memory. It could be done almost as easily by amending instructions in memory. In fact, the Univac Solid State Computer offered index registers as an option in the early 1960s, but there was little takeup.[2] --Malleus Fatuorum 19:37, 8 February 2009 (UTC)

Re Univac, I suspect that's because in the 1950s they'd followed the line (later attributed to IBM) "if you find a deficiency, call it a feature and sell the benefits" :-)

And of course self-modifying code was quickly found to be a can of worms.

I haven't found for WP:RS for index regs as a big factor in IBM's rise to dominance, maybe it was just folklore in my early days in computers. --Philcha (talk) 22:51, 8 February 2009 (UTC)

• Lavington (1998) says that Williams saw ENIAC on a visit to the US in 1946, and that the summer school at the Moore School of Elecrical Engineering was to design EDVAC, ENIAC's successor. Wilkes (EDSAC) attended the summer school, but none of the Manchester group did. The only apparent inspiration Williams got from his visit was from ENIAC's demonstration that a machine containing 18,000 valves could be kept error-free for long enough to do some useful work. (Might be worth adding that to the SSEM article.) "None of the Manchester group and few people in the United Kingdom generally were in direct contact with ENIAC or the EDSAC EDVAC designers." --Malleus Fatuorum 12:56, 9 February 2009 (UTC)

Would be worth clarifying how much info was transferred when, with refs. By "EDSAC designers" do you mean "EDVAC designers"? EDSAC was British.

The reliability issue is definitely worth mentioning. --Philcha (talk) 16:10, 9 February 2009 (UTC)

No information was transferred. Manchester Mark 1 owed nothing to ENIAC or to EDVAC, other than the insight than a machine composed of 18,000 valves could actually work. --Malleus Fatuorum 23:09, 9 February 2009 (UTC)

Background

• Should point out that the Manchester team got a lot of ideas from Eckert & Mauchly's summer school about ENIAC, see sources I found. Sorry I can't remember which sources say what, that's the disadvantage of speed-reading. --Philcha (talk) 00:03, 9 February 2009 (UTC)
  • No, they didn't, see my comment above. None of the Manchester group attended the summer school, which was about the design of EDVAC, not ENIAC. --Malleus Fatuorum 13:03, 9 February 2009 (UTC)
• Should point out that von Neumann publicised the stored program concept in the 1945 First Draft of a Report on the EDVAC, based on discussions with Eckert & Mauchly, who were held back for implementing their ideas by a "freeze" order on ENIAC, but managed to build on a limited read-only stored program capability in 1948. --Philcha (talk) 00:03, 9 February 2009 (UTC)
  • Mention of the von Neumann architecture was relevant in the SSEM article, but I don't see that it bears repeating here. Neither do I see the relevance of Eckert & Mauchly's 1945 paper. --Malleus Fatuorum 15:37, 9 February 2009 (UTC)

I'd add "publicised by John von Neumann's paper First Draft of a Report on the EDVAC in 1945" - to methat's mor einteresting than the endianess of any m/c, which is only important for binary programming and for dump-reading. --Philcha (talk)

Well, I don't agree. --Malleus Fatuorum 19:25, 9 February 2009 (UTC)

• The whole business could do with a time line - I suggest a compact right-floated table. Should focus on Mark 1 (prototype, Intermediate and Final versions) but show other important events, e.g. First Draft of a Report on the EDVAC (1945), Eckert & Mauchly's summer school (can't remember when), limited read-only stored program capability for ENIAC (1948), EDSAC, Ferranti Mark 1 lifetime, IBM 701. --Philcha (talk) 00:03, 9 February 2009 (UTC)
  • This article is about the Manchester Mark 1, which was a prototype only in existence for a little over two years. and in its final form for just one. It owed nothing to Eckart & Mauchly's 1946 summer school. A timeline would be rather short and overkill IMO. --Malleus Fatuorum 13:08, 9 February 2009 (UTC)
• The para about "Baby" looks rushed and unclear. Needs to separate the sub-topics of memory tech and stored programs, probably in separate paras. Then explain briefly the pros & cons of Williams tubes (advantage was random access to whole words as opposed to bit-sequential access on mercury delay lines, see e.g. http://www.cs.ucf.edu/courses/cda5106/summer03/papers/mark1.atlas.1.pdf; downside doubts about reliability, and some of the sources I found describe the problems and solutions, just cite them w/o details) and of stored programs (faster set-up compared w ENIAC, where it took days to set up a program and minutes to run it). If I've read some of the sources correctly, the combination of Williams tubes and stored program had other benefits (whole > sum of parts)- checkpoint/restart by saving memory to drum, program overlays and saving of common routines on the drum (the beginnings of reusability), which depended on the fast access time of the tubes. --Philcha (talk) 00:03, 9 February 2009 (UTC)
•  Not done The phrase proof of concept might be useful to describe "Baby" and set up comparison with Mark 1, which was meant to be capable of real work. --Philcha (talk) 00:15, 9 February 2009 (UTC)
  • Mark 1 was meant as a prototype for the Ferranti Mark 1; the fact that it could be used to do useful work while the university was waiting to take delivery of the first Ferranti Mark 1 was really just a bonus. --Malleus Fatuorum 13:19, 9 February 2009 (UTC)

That appears inconsistent with your report that Lockspeiser saw "a demonstration of the prototype Mark 1" and then initiated the Ferranti Mark 1 commercial implementation. Or perhaps you've over-summarised the chain of events? --Philcha (talk) 16:10, 9 February 2009 (UTC)

The aim was initially to develop a realistic computing facility for the university, but that changed after Lockspeiser saw the demonstration. I'll try to make that clearer. --Malleus Fatuorum 19:25, 9 February 2009 (UTC)

Done, hopefully. --Malleus Fatuorum 21:01, 9 February 2009 (UTC)

"From about August 1948, the SSEM was intensively developed as a protype for the Manchester Mark 1, with the aim of providing the university with a more realistic computing facility" doesn't do it for me:

• "the SSEM was intensively developed as a protype for the Manchester Mark 1" makes it look like the prototype Mark 1 Lockspeiser saw was SSEM with bolt-on goodies. --Philcha (talk) 22:16, 9 February 2009 (UTC)
• which would seem to imply that the Manchester Mark 1 had separate objectives, not defined in the article, but not including leading to the Ferranti Mark 1, as that only became part of the plan after Lockspeiser's visit. --Philcha (talk) 22:16, 9 February 2009 (UTC)

• I'd move the para "In October 1948, UK Government Chief Scientist Ben Lockspeiser ... and involved an estimated £35,000 per year" to the "Consequences" section. --00:03, 9 February 2009 (UTC)
  • I think it's important that paragraph stays in Background, as it clearly establishes that the Mark 1 was intended as a prototype for the Ferranti machine, not as a finished machine like EDSAC. --Malleus Fatuorum 13:17, 9 February 2009 (UTC)

See above. --Philcha (talk) 16:10, 9 February 2009 (UTC)

•  Done Wherever that para winds up, a conversion to current money values would be helpful. I've used Five Ways to Compute the Relative Value of a UK Pound Amount, 1830 to Present in chess history articles (a prize of £100 was serious money around 1850). You'd have to select and justify which of the indices you use; I normally use incomes. --Philcha (talk) 00:03, 9 February 2009 (UTC)
  • Done, using {{Inflation}}, which will keep the conversion up-to-date. --Malleus Fatuorum 13:31, 9 February 2009 (UTC)

Nice, I'll add that to my toolkit, thanks! --Philcha (talk) 16:10, 9 February 2009 (UTC)

Development and design

• I think the structure of this section is rather muddled. In particular the first para flip-flops between develpoment history and functional capabilities, without defining the functional elements. I suggest:
  • Quick summary of main components in the Final version (state that this summarises Final version): Williams Tubes as RAM (a term the majority of readers will recognise from computer ads, unlike "main store"); drum as long-term data storage (i.e. data was not lost when it was powered off; no need for "non-volatile"; easier to understand than "backing storage"); paper tape as main input, paper tape and teleprinter for main output; CRT as console display, what it showed controlled by switches; processor that ran programs, i.e. initiated I/Os, did calculations, took decisions; including index register, an innovation that made some common operations like stepping through rows of a table much easier to program (I think this is a more intelligible way of explaining it than "convenient iteration through an array").
    • "Stepping through rows of a table"? What table? --Malleus Fatuorum 22:49, 9 February 2009 (UTC)

A table is 1-D array of fixed-length records / structures / whatever your favourite language calls them. Index registers are at their best for stepping through the least "significant" (most repeated) dimension of arrays - and for that they are great. --Philcha (talk) 23:14, 9 February 2009 (UTC)

The point I was making is that there are no "tables" in memory. --Malleus Fatuorum 14:19, 10 February 2009 (UTC)

• • Fuller description of components and capacities.
  • Development history, with capabilities missing / added at each stage. Should include the prototype seen by Lockspeiser in Oct 1948. I think that implies that the material about use of switches for input and CRT for output in "Programming" should be moved here.--Philcha (talk) 01:48, 9 February 2009 (UTC)
• The diagram shows no output device. OTOH I'm not sure that showing each of the (?) logic gates helps non-specialist readers. And what the heck was the "Staticisor"? I'd also be inclined to use template:Annotated image as that makes diagram text much clearer at thumb-like sizes, see for example Arthropod#Segmentation. --Philcha (talk) 01:48, 9 February 2009 (UTC)
  • The diagram is based on Kilburn's own schematic diagram from his 1949 Nature paper. He doesn't show any output devices, although there was an output tube which could be switched to show the contents of any other tube, as on the SSEM, as well as the teletype. I'll try to explain what the staticisor did in a new paragraph on the general operation of the machine. Basically it was used to hold instructions while they were being worked on. --Malleus Fatuorum 21:09, 9 February 2009 (UTC)
  • That template has the significant disadvantage that the text would have to be removed from the diagram, thus making it useless at its full size. --Malleus Fatuorum 14:19, 10 February 2009 (UTC)
• "1,024 (2¹⁰) different instructions" appears here and in "Programming", I think it should appear only in "Programming". --Philcha (talk) 01:48, 9 February 2009 (UTC)
  • Done. --Malleus Fatuorum 13:37, 9 February 2009 (UTC)
•  Done Was it able to handle fixed point arithmetic, e.g. 1.5 + 2.3? (in IBM mainframe assembler, programmers calculate the result's precision and then apply an edit mask to put the dot in the right place for printing / display, and stripping the dot out of input is even more fun; compilers build similar operations into generated code). --Philcha (talk) 01:48, 9 February 2009 (UTC)
  • Any machine, including the Manchester Mark 1, can handle fixed point arithmetic by using implied decimal points. It does mean though that the programmer has to keep track of the precision, as you say. --Malleus Fatuorum 15:33, 9 February 2009 (UTC)
•  Done How was arithmetic handled internally, in decimal or binary? If binary, was it able to convert for input / output, or did users have to convert the hard way? --Philcha (talk) 01:48, 9 February 2009 (UTC)
  • Binary, the machine did the binary-decimal-conversions itself. Added a sentence to say that. --Malleus Fatuorum 14:17, 9 February 2009 (UTC)

Thanks. Philcha (talk) 16:28, 9 February 2009 (UTC)

Programming

• "Thus "10010" represents "D", "10001" represents "Z", and so forth. Turing changed only a few of the standard encodings; for instance, 00000 and 01000, which mean "no effect" and "linefeed" in the teleprinter code, were represented by the characters "/" and "@" respectively" does nothing for me, and I think the artcile would be better without it, going straight from "The ITA2 system maps each of the possible 32 binary values that can be represented in 5 bits (2⁵) to a single character" to "Because the Mark 1 had a 40-bit word size, eight 5-bit teleprinter characters were required to encode for each word." --Philcha (talk) 01:48, 9 February 2009 (UTC)
  • I think it's interesting that Turing was the one who devised the modified ITA2 encoding system, so would prefer to see this material stay. There's also an anecdote that I meant to add about the significance of him choosing "/" to represent binary zero. --Malleus Fatuorum 14:20, 9 February 2009 (UTC)
• Re "The Mark 1 had no system of hardware interrupts; the program continued after a read or write operation had been initiated until another input/output instruction was encountered, at which point the machine waited for the first to complete":
  • I think this would be better as part of the list of capabilities (or lacks) in "Development and design".
  • How did Mark 1 wait for a tape / printer I/O to complete, if there were no hardware interrupts? Do you mean programmers had to calculate the I/O completion time and ensure their code executed exactly the right number of instructions between request and completion? If so, should explain this, as most modern programmers work in blissful ignorance (except microcode programmers). --Philcha (talk) 01:48, 9 February 2009 (UTC)
•  Done Presumably once tape input was available programs were input in the 5-bit character coding, which the programmers had to look up / memorise? --Philcha (talk) 01:48, 9 February 2009 (UTC)
  • That's right, in fact programmers were encouraged to learn the encoding by heart. --Malleus Fatuorum 14:26, 9 February 2009 (UTC)

I've just seen "The user is strongly recommended to learn the above table" in the ref. Ah, the not-so-good old days. --Philcha (talk) 16:32, 9 February 2009 (UTC)

Perhaps more recent than you might think. In the 1970s I worked for Olivetti, programming one of their machines in binary and memorizing the assembler codes, just like on the Mark 1. --Malleus Fatuorum 21:33, 9 February 2009 (UTC)

Just like you did on the Mark 1? --Philcha (talk) 22:18, 9 February 2009 (UTC)

• Some of the material here would be better in "Development and design"'s list of capabilities: "Data was read and written from the papertape punch under program control"; possibly "The Mark 1 had no system of hardware interrupts; the program continued ... waited for the first to complete"; number range it could represent. --Philcha (talk) 01:48, 9 February 2009 (UTC)
• I don't think the endianness is important at this level of artcile (it's not a programmer's guide) and suggest removing it. --Philcha (talk) 01:48, 9 February 2009 (UTC)
  • I think it's interesting and see no harm in keeping it. --Malleus Fatuorum 14:17, 9 February 2009 (UTC)

Further developments

• I suggest splitting this into 2 sub-sections - one for the Mark 1 lineage (Manchester & Ferranti), including Meg, and another for other lineages influenced by Mark 1 (mainly IBM 70x). --Philcha (talk) 14:36, 9 February 2009 (UTC)
• Ferranti Mark 1's Autocoder language provided a form of virtual memory. The hardware features on which this was based were already present in M.M. 1, although Autocoder was only added by Ferranti in 1954. (http://www.cs.ucf.edu/courses/cda5106/summer03/papers/mark1.atlas.1.pdf; Lavington 1993) --Philcha (talk) 14:36, 9 February 2009 (UTC)
  • The hardware feature Autocode made use of was memory paging between the magnetic drum and main storage, which is already covered in this article. Autocode was developed on the Ferranti Mark 1 anyway, a quite different machine from the Manchester Mark 1, and appeared four years after the Manchester Mark 1 had been scrapped, so I don't see its relevance to this article. --Malleus Fatuorum 15:27, 9 February 2009 (UTC)

Already covered, but not very explicit and buried in a para that contains other topics.

As I commented re the "Design & Development" section, the elements need to be separated and made more explicit. And sources indicate that "paging" was not just for "one-level storage" but was also used as an early version of checkpoint/restart, in case of tube or other failure. In that respect it's a precursor of the IBM 650. --Philcha (talk) 16:48, 9 February 2009 (UTC)

Lavington 1978 is quite explicit about Manchester's influence on memory management - I suggest that's a must-have. --Philcha (talk) 17:00, 9 February 2009 (UTC)

Isn't that just a programming issue, already covered by the discussion of paging on the magnetic drum? I feel it necessary at this point to remind you that comprehensiveness is not one of the GA criteria. --Malleus Fatuorum 23:17, 9 February 2009 (UTC)

"comprehensiveness is not one of the GA criteria" - yet you include endianness and details of the 5-bit TT code :-)

Non-programmers and, I suspect, quite a lot of programmers (especially those who use e.g. VB or Delphi) will not make the step from M.M 1's paging to virtual memory, so you have to give them a bit of help. Even Lavington (1978), writing for other experts, thought it worthwhile to mak ethe point quite emphatically.

I think before we discuss the details any further we ought to discuss the issue of perspective (below). --Philcha (talk) 23:44, 9 February 2009 (UTC)

• IBM 70x series used Williams tube memory up to & incl IBM 709. This m/c was short-lived (1958-1959) as US military customers wanted an all-transistor m/c, and the IBM 7090 (1959 to the introduction of IBM System/360) was a transisitorised 709. --Philcha (talk) 14:36, 9 February 2009 (UTC)
  • Interesting to read in an article about the IBM 70x series, but here? In any event, the IBM 709 used core storage, not Williams tubes.[3] --Malleus Fatuorum 15:18, 9 February 2009 (UTC)

Looks like I got mixed up on the details while speed-reading the sources I found.

However there's still a story to tell here. Williams tube lists a range of m/cs that used them, incl some early Univacs (although the 1st used delay lines; so Univac switched!), and the Soviet Strela - unfortunately w/o refs. I think the story is that SSEM was a successful pilot of Williams tubes and M.M 1 showed that they scaled up and were reliable enough - and then widely used, until core memory became available. --Philcha (talk) 16:48, 9 February 2009 (UTC)

Looks to me like you keep getting mixed up. --Malleus Fatuorum 23:19, 9 February 2009 (UTC)

How? Was not SSEM a successful pilot of Williams tubes? Did M.M 1 not show that they scaled up and were reliable enough? Did not alot of subsequent m/cs use Williams tubes? --Philcha (talk) 23:44, 9 February 2009 (UTC)

• However the IBM 70x also used other design ideas from American institutes, see some of the sources I found. --Philcha (talk) 14:36, 9 February 2009 (UTC)
  • I don't see how this is relevant in article about the Manchester Mark 1? --Malleus Fatuorum 15:12, 9 February 2009 (UTC)

Objectivity: the M.M 1 was a strong influence on later computers but not the only one. --Philcha (talk) 16:48, 9 February 2009 (UTC)

Do you have a reference for "strong influence on later computers"? I don't. --Malleus Fatuorum 23:14, 9 February 2009 (UTC)

If Williams tube is right despite its lack of refs, a lot of subsequent mcs used Williams tubes.

Index regs were one of the patents IBM licensed, and used throughout the 70x series (and later, e.g. 360 and successors) that made them the dominant supplier.

Lavington 1978 is quite explicit about Manchester's influence on memory management. --Philcha (talk) 23:44, 9 February 2009 (UTC)

Refs

• These say "Lavington 1998", should be 1993. Paper is freely available online at http://www.cs.ucf.edu/courses/cda5106/summer03/papers/mark1.atlas.1.pdf, please add url & accessdate. NB IEEE Xplore page accessed via doi gives a link but it returns an error. --Philcha (talk) 14:46, 9 February 2009 (UTC)
  • No, I have it in front of me, and it's definitely 1998, not 1993. It's a book, published by the British Computer Society, not a paper. --Malleus Fatuorum 15:10, 9 February 2009 (UTC)

Sorry, you're right - I haven't seen a "References" section split like that before, although I think it's a good idea; do I have you permission to copy it? ---Philcha (talk) 15:40, 9 February 2009 (UTC)

Feel free to copy anything you like, I always do. :-) --Malleus Fatuorum 15:43, 9 February 2009 (UTC)

Perspective

The contrast between my comments and your responses indicates that we need to reach agreement on the article's perspective.

My view is:

• It should be written for non-specialists. In this case I think that means primarily readers with no programming experience, followed by those who have used only relatively cushy development environments - e.g. Javascript, VB or Delphi on the client side; MS ASP, PHP, Cold Fusion, Java, etc. on servers; C / C++ for the few who write systems software.
• So I think the main points to be brought out are:
  • How primitive computers, incl Mark 1, were in the late 1940s - no OS, no assembler, no hardware interrupts; consequences of these "deficiences".
  • Lavington 1993's table of vital statistics would illustrate how primitive late 1940s m/cs were, even compared with mid-1950s ones. If you throw in bulk and / or weight, power consumption and (where available) inflation-adjusted cost, that will really make an impression.
  • Nevertheless the late 1940s pioneers, notably the Manchester team, introduced many concepts that are became important: the advantages of high-bandwith, random-access memory (see Manchester Small-Scale Experimental Machine on disadvantages of mercury delay lines); index registers; reusable code; the hardware infrastructure for virtual memory, although software support (Ferranti Autocode) arrived only in 1954 and that lineage never had dynamic address translation hardware (AFAIK introduced with the design of Compatible Time-Sharing System, in the late 1950s).
• Technical details should be just enough to make these points and no more - this is not a programmer's guide. --Philcha (talk) 15:46, 9 February 2009 (UTC)
• I really could hardly disagree more with your perspective Philcha. This article, like every other GAN, ought to be judged against the GA criteria. Not against your idiosyncratic ideas of what it ought or ought not to cover. If you believe that it fails on criterion 3 then so be it, fail it and let's get to GAR; I'm not changing the article to suit your perspective. I believe it to be a good (by no means perfect or comprehensive) account of the Manchester Mark 1, which it would not be if I followed your suggestions. --Malleus Fatuorum 23:05, 10 February 2009 (UTC)

• Comments from Pyrotec- Sorry, but I fundamentally disagree with Philcha. My background was DOS (or MSDOS), BASIC, Fortran 77, Pascal and I have used a teletype and punched paper tape for input, so I have sympathy with identifying primarily with readers with no programming experience, but I have no interest in "cushy development environments - e.g. Javascript, VB or Delphi on the client side; MS ASP, PHP, Cold Fusion, Java, etc. on servers; C / C++". So I don't see why the article should be distorted to fit those needs. Producing a whole load of defects - no graphical operating system, no CD-rom or DVD-player, no spreadsheets, comes under the category of "stating the bleeding obvious". I would award the article GA-status now. It would be great if I could find some typos or grammatical errors, especially as "MF" is the nominator, but I have better things with to do with my time than hunting for them; and I'm in favour of adding worthwhile improvements. So in summary, "It should be written for non-specialists" is probably the only thing that I agree with in your "Perspective".Pyrotec (talk) 19:54, 10 February 2009 (UTC)

Conclusion of review

Regretfully I do not believe that this article currently meets the GA criteria. Although as there is a lot of good research here, it still has the problems I raised above, :

• (criterion 3a) Although it mentions the index register(s), it omits some aspects of the Mark 1's significance: its contributions to the development of virtual memory (stated emphatically by a good source I found and mentioned in a comment); the fact that Williams tubes, used by the Mark 1, quite rapidly displaced mercury delay lines as the standard memory technology. It fails to explain well to a non-specialist reader how much more difficult programming was in those days because of the lack of an assembler, hardware interrupts and an operating system. It also still omits the advantages of Williams tubes over mercury delay lines as a memory technology (cheaper, lighter, did not require such precise temperature control).
• (criterion 3b) It goes into unnecessary detail on some points, notably on endianness and on character assignments in the 5-bit code used for the printer and tape reader and punch. The latest version also goes into a little too much detail on the origins of the stored program idea, for example Zuse had no direct connection with the Manchester team.
• Although the prose is good, the article is unclear on the important point of the Mark 1 project's inital objectives and when and why they changed. The clearest statement is in the lead, but it does not quite match the various parts of the text which deal with this point. I'm not sure whether this is a matter of presentation or whether the sources are not explicit. --Philcha (talk) 23:57, 10 February 2009 (UTC)

- - - - - please add review comments /responses above this line - - - - -
If you want to start a new section of the Talk page while this review is still here, edit the whole page, i.e.use the "edit" link at the top of the page.

Sources

These might be useful sometime: --Philcha (talk) 21:32, 8 February 2009 (UTC)

• The Manchester Mark I and Atlas: A Historical Perspective (S.H. Lavington; 1977: ACM) - general overview, comparison, successor m/cs.
• Electronic computers: a historical survey (S. Rosen; Mar 1969; Compouting Surveys, vol 1, issue 1) - general history; Univac lost to IBM by poor salesmanship, poor integration of acquired companies' techs, and failure to offer rental options (parent co. Remington was financially stretched), unreliable delivery and poor post-sales support
• The First Computers (Rojas & Hashagen, 2002, MIT Press) - esp. "The Manchester Mark 1 Computers". pp 365ff. --Philcha (talk) 22:22, 8 February 2009 (UTC)
• Alan Turing's Automatic Computing Engine (B.J. Copeland; 2005; OUP) - focus on British developments. --Philcha (talk) 22:34, 8 February 2009 (UTC)
• Concise Encyclopedia of Computer Science (E.D. Reilly; 2004; Wiley) - nice timeline in App III, pp 831ff --Philcha (talk) 23:01, 8 February 2009 (UTC)
• History of Computer Memory - the Atanasoff-Berry Computer was apparently the 1st digital computer (voided the Eckert-Mauchly patent) and used a sort of drum memory (capacitors, not magnetised iron). The First Electronic Computer (A.W.Burks; 1989; U of Michigan Press) makes similar points at great length. --Philcha (talk) 20:01, 9 February 2009 (UTC)
• Harvard Mark III had a drum, went live Aug 1949. Volume 7, The Computer Museum Report, Winter/1983/84 claims "Magnetic drum storage was pioneered on the Harvard Mark III". Hmmm. Was Manchester Mark 1's drum operational when Lockspeiser saw the demo in Oct 1948? --Philcha (talk) 20:01, 9 February 2009 (UTC)

Useful resources, thanks. I've been trying to discover the exact number of vacuum tubes in the Mark 1 for ages. --Malleus Fatuorum 21:54, 8 February 2009 (UTC)

It also reminds me that there's an overarching article to be written on the Manchester computers. --Malleus Fatuorum 22:29, 8 February 2009 (UTC)

Have you seen this article - it talks of Drum memory being used pre 1940 - Drum_memory --Chaosdruid (talk) 01:45, 12 February 2009 (UTC)

Problem

This article repeatedly refers to the Manchester Mark 1 as "one of the earliest stored-program computers" and links the stored-program to Von Neumann architecture. These terms are not synonymous.

A Von Neumann architecture has a dedicated memory for storing instructions which is separate from the memory used to store the program data. Von Neumann architectures are frequently contrasted with Harvard architectures, which use the same memory to store both programs and instructions. However, *both* Von Neumann and Harvard architectures store the program somewhere.

It would be more accurate to contrast a stored program computer (be it a Harvard or Von Neuman design) with a single purpose computer with a hardwired program (ala, the Atanasoff–Berry Computer), or perhaps with a reprogrammable computer that uses a physical medium (like punch tape) for program storage rather than electronic.

I've turned Stored-program computer (which was previously a bad redirect to Von Neumann architecture) into a legit article. I'm going to link the terms from here to there. Raul654 (talk) 06:55, 10 November 2010 (UTC)

How many pages per Williams tube?

According to Nature, Vol 164, Oct 22,1949, p684. Dr. T. KILBURN http://www.digital60.org/birth/manchestercomputers/mark1/documents/natureart.html

"A single storage tube has a capacity of 2,560 digits, arranged in two rasters of television type, where each raster has 32 lines, and each line of a raster holds 40 digits."

- that is, each Williams tube held two pages, not one.

86.141.196.130 (talk) 23:37, 5 January 2014 (UTC)

Exact description of Final Spec store size

It seems to me that:

"The capacity was increased to 4 Williams tube and 128 magnetic drum pages in the Final Specification version."

is incorrect, since that phrasing indicates that only four pages of main store were implemented when in fact four tubes were used to provide eight pages.

Thus, a formulation such as:

"The capacity was increased in the Final Specification version to eight pages of main store on four Williams tubes and 128 magnetic drum pages of backing store."

seems to be called for: correctly describing the amount of store provided in a fairly concise and very clear manner.

86.141.196.130 (talk) 00:03, 6 January 2014 (UTC)

Obviously I don't agree, as now we've established that the Mk I used double-density Williams tubes anyone can easily work out for themselves how many pages of main store that represents. But I'm fed up arguing the toss with you. Eric Corbett 00:38, 6 January 2014 (UTC)

The way I look at it, the reader shouldn't have to work things out like that; indeed, requiring the reader to work out things like that is sure to result in many readers misunderstanding what's written.

The text should be written clearly so the reader can understand it without trouble. If it's practical to help the reader avoid mistakes in comprehension, then the text should do so.

(one must be careful to avoid wind-baggery when trying to do this - I think I've managed that much at least)

One problem is that the term "double-density" tubes doesn't help - what's a "single-density" tube? Implicitly, one of half the capacity of a double-density tube. But that's all we get from the phrase - and then only if you make the link between "density" and "capacity" (which most would, I'd hope). How does that help anyone? I don't get it. Double-density might be a correct term, but it's not an aid to reader understanding of the article in my view.

Stating plainly that the tubes in question each held "two arrays of 32 x 40-bit words – known as pages": that's helpful.

Back to your suggested phrasing:

"The capacity was increased to four Williams tubes and 128 magnetic drum pages in the Final Specification version"

Is indeed no longer an incorrect statement - "4 Williams tubes" rather than "4 Williams tube [...] pages".

However, I think a reader could easily slip up and misunderstand what was meant, so it's a better idea to explain things clearly. Since it's easy enough to do so without being long-winded about it, why not leave my phrasing in place?

My point is not that your phrasing is wrong, just that it's liable to lead to misunderstanding which could very easily be avoided.

86.141.196.130 (talk) 01:01, 6 January 2014 (UTC)

Main and backing store description.

I feel it is helpful to describe the size of the working stores not only in terms that describe the machine architecture - that is, in terms of pages - but also in terms of words. My reasoning is that it's easier for the reader to comprehend both the machine architecture and the size of store provided if store size is described both as number of pages and number of words.

It is also (obviously to my mind) helpful to explain what is meant by "backing store", since the concept is not obvious.

Finally, the term "double density" when applied to Williams tubes is not helpful to the reader for the following reasons:

1: "Single density" is not defined.

2: For the term to carry meaning, the reader must understand that the "density" described is an areal density, and that area has been conserved from "single" to "double" density storage devices.

For those reasons, it makes sense to remove the reference to "double density" since it does nothing to aid reader comprehension.

I suggest that my edits be left to stand unless there are clear reasons to contradict any of my reasoning. 86.141.217.115 (talk) 01:46, 28 January 2014 (UTC)

I would like to remind editors of this page of Wikipedia_talk:Civility#Pillars:

Wikipedia operates on the following fundamental principles, known as the five pillars:

Editors should interact with each other in a respectful and civil manner. Respect and be polite to your fellow Wikipedians, even when you disagree. Apply Wikipedia etiquette, and avoid personal attacks. Find consensus, avoid edit wars, and remember that there are 6,916,101 articles on the English Wikipedia to work on and discuss. Act in good faith, and never disrupt Wikipedia to illustrate a point. Be open and welcoming, and assume good faith on the part of others. When conflict arises, discuss details on the talk page, and follow dispute resolution.

I wish to discuss this matter courteously in order to avoid an edit war. I assume good faith on the part of other editors of this article. 86.141.217.115 (talk) 02:07, 28 January 2014 (UTC)

What's wrong with this description of storage? (attempting to resolve disagreement)

The SSEM's 32-bit word length was increased to 40 bits. Each word could hold either one 40-bit number or two 20-bit program instructions. The main store initially consisted of two Williams tubes, each holding two arrays of 32 x 40-bit words – known as pages – with a backing store provided by a magnetic drum capable of storing an additional 32 pages (128 words main store; 1024 words backing store). The capacity was increased in the Final Specification version to eight pages of main store on four Williams tubes and 128 magnetic drum pages of backing store (256 words main store; 4094 words backing store).

The magnetic drum memory on the Mark 1 was not file store, but was used as part of the computer's working memory rather like a crude version of virtual memory, with transfers between slow magnetic drum and fast Williams tube main store being intiated by programmed instructions. The 12-inch (300 mm) diameter drum, initially known as a magnetic wheel, contained a series of parallel magnetic tracks around its surface, each with its own read/write head. Each track held 2,560 bits, corresponding to 2 pages (2 x 32 x 40 bits). One revolution of the drum took 30 milliseconds, during which time both pages could be transferred to the CRT main memory, although the actual data transfer time depended on the latency, the time it took for a page to arrive under the read/write head. Writing pages to the drum took about twice as long as reading. The drum's rotational speed was synchronised to the main central processor clock, which allowed for additional drums to be added. Data was recorded onto the drum using a phase modulation technique still known today as Manchester coding.

86.141.217.115 (talk) 03:01, 28 January 2014 (UTC)

It is disappointing to see this sort of to-ing and fro-ing between two editors. It is not a dispute of fact or interpretation, only one of style of expression. Clarity is of great importance and we should always strive for it. I admit to a slight prejudice against un-registered, anonymous editors, as in my experience, their edits are often un-helpful or vandalism. However, my preference on this occasion is for the version by 86.141.217.115 over that by Eric Corbett, with the following exceptions. (1) I marginally prefer "backed up by a magnetic drum" to "with a backing store provided by a magnetic drum", as it gradually introduces the reader to the concept in the phrase "backing store" that is used later, and which may be new to them. (2) I am unsure as to whether "rather like a crude version of virtual memory" is helpful for the less well-informed reader and it could well be deleted. I am not going to change the article just yet and would encourage others to express their views. --TedColes (talk) 11:47, 28 January 2014 (UTC)

Thank you for your well considered feedback.

The problem with the phrase "backed up by a magnetic drum" to my mind is that it makes the mag drum sound like a modern "file backup store", which it wasn't. Admittedly, the drum did get used to back up (in the modern sense) intermediate results against errors occurring during a run (the machinery was prone to intermittent faults - i.e., in modern terms, the thing was flaky as hell), but "file store" in the modern sense was on punched paper tape.

On the other hand, "backing store" isn't as usefully self-explanatory as maybe I'd thought. This needs some more thought.

I agree with your point regarding the analogy to virtual memory. Still, I think something needs to be done to explain how this part of the machinery worked rather than leaving it up to the reader to work it out from implication. On the other hand, how exactly was the magnetic backing store used? The more I read on the subject, the more it seems that the users of the Manchester Mark 1 (as opposed to the Ferranti Mark 1) used it in any way they thought useful. After the Manchester Mark 1 had been scrapped and Autocode was developed, the way in which the backing store got used was (for users of Autocode at least) seemingly settled by the software.

I don't know what to do about this and shall think about it.

Regardless of all that, I don't see any possible argument against expressing the store size in words as well as pages. Any comments from anyone?

86.141.217.115 (talk) 14:25, 28 January 2014 (UTC)

I have read through the two versions of the article. I am broadly in favour of Eric's version, but I prefer 86's decision to not include the phrase "double-density" referring to the Williams tubes, which has not been defined or linked by that point in the article. CRT should not have a link, as cathode ray tube (CRT) is defined earlier in the article. The problem with technical details is you need a balance between being a good definition of the computer's features, but one that a typical layman reader would understand. A non-expert would still understand the concept of bytes and storage through waiting for a file to copy on Windows, for example. Ritchie333 ^{(talk) (cont)} 07:56, 29 January 2014 (UTC)

As someone who used to teach people how to use Windows computers, I'm sorry to report that most people do not pick up the concepts of bytes and storage in the way you think they should (FWIW, I've found every Windows UI since Windows 3.11 to be progressively more confusing). These are things which need to be explained carefully to a lot of people. Lots of people need every concept relating to a computer filing system explained one step at a time to understand it, which isn't to say that they're stupid or slow on the uptake, just that they've not had a chance to learn and need information.

However, you can't provide that sort of explanation in every computing-related article: some sort of judgement needs to be applied on what you can expect the reader to know. I work on the basis that they've got some understanding of very basic concepts, i.e., what a "bit" is and the idea that you keep the things in what gets called "storage" or "memory" or what have you. But it's all very subjective and hand-waving, is this sort of judgement.

What do you think of the addition of storage size in words? E.g., "The capacity was increased in the Final Specification version to eight pages of main store on four Williams tubes and 128 magnetic drum pages of backing store (256 words main store; 4094 words backing store)"

Michael F 1967 (talk) 05:34, 30 January 2014 (UTC)

Just to clarify, I simply mean that people have heard of the word "byte" and know it's something to do with computers. In the case of the Mark I, I would stick with "word" as "byte" is widely assumed to be 8 bits long - there's no point simplifying things to the point of being factually wrong. The essays on writing better articles and basic copyediting have further information. Ritchie333 ^{(talk) (cont)} 08:42, 30 January 2014 (UTC)

Thanks for the pointers, although I'm not sure which parts of those two very helpful articles you think are particularly applicable to this job. My recent edits were focussed on the ideas discussed in Wikipedia:BETTER#Provide_context_for_the_reader.

On the subject of the term "byte" with respect to the Manchester Mark 1:

Given that "Historically, the byte was the number of bits used to encode a single character of text in a computer", it could reasonably be said that the Manchester Mark 1 used eight five bit bytes to the [40 bit] word - which is out of line with current general usage. The term "byte" was coined about six years after the Mark 1 had been scrapped. For those two reasons, I'd suggest that the word "byte" has no role in describing the Manchester Mark 1.

Michael F 1967 (talk) 23:33, 4 February 2014 (UTC)

Suggestions please on how to resolve problems with User:Eric_Corbett

I've been trying to resolve the difference of opinion I have with User:Eric_Corbett using discussion.

The nearest thing to a substantial response I've managed to get from him is:

User_talk:Eric_Corbett#Notice_of_Edit_warring_noticeboard_discussion

"I haven't read your comments anywhere, as I have absolutely no interest in anything you might have to say. Eric Corbett 14:46, 28 January 2014 (UTC)"

Clearly, if User:Eric_Corbett won't engage in discussion with me, there's no way of resolving any differences of opinion we might have, which is just as obviously bad for any Wikipedia pages where we might have a conflict of ideas.

I'd appreciate any suggestions on what I should do next.

86.141.217.115 (talk) 16:11, 28 January 2014 (UTC)

What to do next? Stop trying, focus on the forward-looking section above this one. If you have suggestions to make, and your suggestions gain supports as improvements over the current Eric-sanctioned version (i.e. more than just swapping minor words) then there is some chance that a cadre/consensus/clique/coven of other editors might support them, despite Eric's views.

Alternatively just walk away and stay well clear of Eric. New editors are not welcome.

As to the EW closure last night, then "stale" isn't the phrase I'd have used, but I can see the virtue in Callanecc's early close of this. You are an unregistered account and a new editor, therefore you will be treated here as an ignorant vandal. An EW action would likely have meant an indef block for you (undeserved, but common) and another trip to the WP:ANI funfair for Eric. Neither of those would have achieved the slightest. Andy Dingley (talk) 16:15, 28 January 2014 (UTC)

Thank you for your comments. (I've had to reboot my router, hence the IP address change). I am indeed focussed on the article, and looking at the feedback I've received above. I am however concerned that Eric will just revert any changes I make, regardless - action which seems out of line with the guidelines I've read on how to work in Wikipedia.

I'm not sure why I should be treated as an ignorant vandal, given the remarks on my edit provided by User:TedColes. Could you explain further?

Could you explain your remark "New editors are not welcome"?

Thank you once again.

86.145.109.150 (talk) 16:42, 28 January 2014 (UTC)

Replying to the comment on my talk page here.

Had I come across the AN3 report sooner than the 9 hours I did there would have been a short block (not indef as Andy suggests) for both of you for violating 3RR. However blocking someone to stop edit warring which had already stopped 9 hours before doesn't achieve anything preventative.

In terms of my comment which said "discuss rather than revert" that does apply to both of you as you both broke 3RR. What you should have done is, once it had been reverted come to the talk page and ask for other opinions (which you have now) rather than edit war.

Given Eric hasn't commented in the section above any agreement between users is enough to warrant making the change, if Eric reverts again then he's reverting against a consensus version without commenting and we/I can use the protect or block buttons. Callanecc (talk • contribs • logs) 00:27, 29 January 2014 (UTC)

Thank you for your kind explanations.

This next bit might sound like I'm trying to excuse past bad behaviour on my part, but that is not my intention. I'd just like to point out that despite my improper "edit warring" behaviour (which I will not repeat now I've learnt better), I did in fact come to the talk page and ask for other opinions after the second reversion of my edits. I also repeatedly urged the other editor involved to engage with me on the talk page. That's why I didn't understand your comment that we should both remember to discuss rather than revert: I might well have been constantly reverting (which I learnt I shouldn't have done), but I had also initiated a discussion on the talk page.

Anyway, I've learnt better and I'll not forget how to deal with such situations in future.

Michael F 1967 (talk) 05:14, 30 January 2014 (UTC)

Just to throw my opinion into this, I don't think you've done anything wrong, Michael. New editors don't come to Wikipedia armed with a full and complete understanding of Wikipedia policies. Keep discussion focused on the Mark I (or whatever article you choose to work on) and avoid conversations about specific editors and their perceived merits, and you should have no problems. Ritchie333 ^{(talk) (cont)} 08:42, 30 January 2014 (UTC)

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