Talk:Harvard Mark I

Arthur Lemay Harvard Class of 1959

In 1955 I was a student at Harvard and spent many hours in laboratory time programming the Univac I prototype, which was located immediately adjacent to the Harvard Mark I computer, and the later Mark II and other early vacuum tube computers.

The Mark I was enormously large and complex, and, at the time when I first saw it, it was running a code for designing lenses for military equipment. This computational task ran for weeks and weeks, and produced all of its results on a set of 10 Flexowriters (really just computer driven typewriters). The programs were not in memory, they were on giant rolls of thick paper the width of the IBM 80 column card. And, there were reading stations for multiple rolls. After watching it for an instant, anyone could grasp the concept of loops since the controls tranferred from one reading station to the other and the execution could be watched while in process. The programmers often applied paper patches on the paper rolls to fix program errors -- these were real patches, and of course the word "patch" is used to this day for temporary changes to any software.

Originally, the memory was implemented with a set of disks the size of saucers mounted on shafts, each with a cam to engage the disk in one of ten positions. The number of disks seemed enormous to me at the time. There was also a very small vacuum tube memory added much later, but the Mark I was really an electromechanical machine.

My fondest memory of early computing was when, one day, the lens program was done and the Laboratory staff set up a new problem for the Mark I to solve.

I watched as two graduate students entered constants into the memory: One was on a stepladder in front of a huge panel with 10-position butterfly switches. The other student yelled out 4, 6, 7, 2, 1, etc., and the first student on the stepladder set the switches for each digit in each memory constant. This took many hours to accomplish because all the constants needed to checked and verified. Then the paper tape programs were mounted and sequenced to their start positions. The next step was the process of actually transferring the fixed constants to disk-on-shaft memory.

There was a very large lever mounted inside the machine on what looked like a transmission box. The lever was quite long, giving good mechanical leverage, and the lever was up in the disengaged position -- withdrawing the cams and letting the disks spin freely on the shafts. The shafts were put in motion, at first giving a low-pitched mechanical humming sound, quieting down as the bearings came up to operating temperature. Then, the student brought the lever down a short way and we heard the most enormous clatter of the cams engaging the disks. Of course the inertia of accelerating the disks caused a strong backlash on the lever and one man could barely hold it. The lever was brought down further and the clatter got even louder and it seemed like the computer was shaking and the lever oscillated up and down violently. Then, suddenly -- total silence -- and the lever dropped home to the engaged position when all the disks on all the shafts were syncronized to the settings on the butterfly switches.

The dynamic memory was implemented in a large array of relays which actually had a very small capacity. This memory was initialized and the tapes commanded to read and execute the codes contained there. This computer ran the problem for weeks.

But, this was the world's first fully automatic computer, and it ran many problems in its lifetime. It is a pity that it no longer exists, but I saw some parts in Museums in Boston and Sunnyvale, California.

Arthur Lemay Harvard Class of 1959

I'm more than tolerably familiar with the machine, and there's something definitely wrong here. There may conceivably have been some lever(s) for disengaging functional units like interpolators for maintenance, or to reduce wear and tear – I don't think so, but it's possible I've missed something – but initiating a computation had no such mechanical step. It was not too long ago that you could actually switch on the drive motor on the half of the machine still resident at Harvard; I did it many times myself for visitors, and it came to life perfectly smoothly, with none of the violence described above. And there was certainly no process of "transferring the fixed constants to disk-on-shaft memory", because that makes no sense. The constants were used as an operand source exactly as the "counters" (adders which doubled as variable storage) were, just they couldn't be changed under program control. I can only imagine that the OP is mixing his memories of the Mark I with those of some other contrivance. EEng 20:42, 23 October 2021 (UTC)

Query

Does anyone know what sort of problems the Mark I was created to solve? I heard it was made to calculate ballistic firing tables for artillery during the war, but I'd like to read that from an authoritative source. I've also never seen a ballistic firing table and wonder what they looked like.

"The History of Mathematical Tables from Sumer to Spreadsheets", ISBN 0198508417 refers to the Mark I as having cranked out 50 volumes of Bessel function tables among other things...--Billymac00 (talk) 02:58, 13 April 2010 (UTC)

Unclear

"The main advantage of the Mark I was that it was fully automatic—it didn't need any human intervention once it started. It was the first fully automatic computer to be completed."

What exactly does this mean? This was Mark I's main advantage compare to what? I also don't see how the ABC, Eniac or Collosus are any "less automatic"?

"the beginning of the era of the modern computer"[2] and "the real dawn of the computer age".[3]

Really? Both of these statements seem odd - this machine is widely regarded as a dead-end, the last of its kind. The debate will rage always, but it moves between the ABC, Collosus and Eniac; the Mark I, and Z-1 for that matter, are always mentioned but generally commented on as not being "real" computers in the modern sense of the word.

Maury Markowitz (talk) 02:07, 23 January 2009 (UTC)

Bel Geddes

According to the Norman Bel Geddes article, he was involved in the design of this machine. 2fort5r (talk) 11:53, 14 July 2009 (UTC)

Questions

Who the hell is "Dr Camila Olmedo Mendez Zegarra"? —Preceding unsigned comment added by 71.15.148.130 (talk) 09:09, 28 February 2010 (UTC)

Pleas do no put in expletives. That name was part of some vandalism stuck into the article. Dmcq (talk) 21:25, 3 September 2010 (UTC)

Heading text

why Howard Aiken named the harvard mark 1 as mark,if he can use the official name Automatic Sequence Controlled Calculator?

More in table

The table and "see also" sections are a bit redundant. And The IBM SSEC needs to go in the table. It was odd in using electronics to do the computation, but relays and tapes to store programs. Used BCD I think, and probably was Turing complete in theory? Ah, that is a separate template. Discussion belongs there.

W Nowicki (talk) 19:42, 23 April 2011 (UTC)

Name

A bit misleading to say "Harvard" renamed it. Most modern sources now call it the "Harvard Mark I", even IBM uses both names. Also I wonder about the front panel. IBM had a history of doctoring photos to make their marketing look slick (ahead of their time?). But would need a source for this. W Nowicki (talk) 23:28, 23 April 2011 (UTC)

Additional Source

http://books.google.com/books?id=PyEDAAAAMBAJ&lpg=PP1&dq=popular%20science%201944&pg=PA86#v=onepage&q&f=true

I was browsing through the Wikipedia article for the UNIVAC computer, and noticed that it contained a citation to a 1949 Popular Science article. This article referenced a 1944 Popular Science article, which I've posted the Google Books link above. I don't really have the time to incorporate this additional information into the Harvard Mark I Wikipedia article, but it seems like a fascinating read. For now, I've added the link to the external references section of the article, but if someone could incorporate the new information, that would be great.

Thanks! Jason Smith (talk) 01:13, 15 February 2012 (UTC)

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Clair Lake

Moving to discuss, with Reify-tech, the formatting of Clair Lake's name in the article, having a tension between:

1. Bold formatting to accommodate redirect from Clair Lake (inventor) as per WP:R#PLA, and
2. Bold formatting is odd; perhaps a WP:REDLINK would be less baffling

I'm not a fan of the redlink, because while it does fix the local problem, it doesn't provide useful information about Clair when redirected from List of National Inventors Hall of Fame inductees, and would be circular unless the Clair Lake (inventor) redirect was removed. Ultimately, the best solution might be to write a page for Clair, although my argument has been that WP:1E suggests that a separate page isn't warranted; in the interim, perhaps the bold formatting would be less surprising if Frank Hamilton's name was also similar formatted. Thoughts? Klbrain (talk) 16:12, 13 March 2020 (UTC)

In accordance with the more-fundamental principle of WP:PLA, most readers would find it very odd that an individual proper name is boldfaced, without any inline textual explanation, footnote, or Wikilink. Readers do not interpret boldfaced terms, lacking an obvious connection to the article title, as a "stub self-link", and are unlikely to be interested in a WikiGnomish technical argument for this formatting distraction that leads nowhere. Additionally boldfacing still more proper names without explanation would just increase confusion and disruption for somebody reading the article for information. I do not know of any examples of articles where this odd formatting actually improves reader understanding.

Even the Wikipedia guideline Help:Self link disparages this unexpected and baffling use of boldfacing, except for two cases that are not applicable here. The valid edge-cases discussed in WP:R#PLA are synonyms or near-synonyms, not obscurely-flagged stubs for further information or articles that do not exist yet. It is far less disruptive to the reader to use either a WP:REDLINK, or to just leave the proper name in regular typeface, and let the reader proceed unmolested.

I strongly suggest leaving the article status quo ante, and allowing any other interested editors at least a week to discuss their views about this. Reify-tech (talk) 17:04, 13 March 2020 (UTC)

Some helpful suggestions there; entirely happy to leave time for discussion. I agree that WikiGnomish argument are subserviant to readability, but argue that bold formatting of key inventors will not be starting to naive editors, who might expect the recognised inventors to be, in some way, emphasised. Klbrain (talk) 17:48, 15 March 2020 (UTC)

Show me some good examples of articles where this idiosyncratic bolding of selected words is not distracting to the reader. WP:RF implies that not startling readers (either naive or experienced) should be more important than arcane WikiGnomery in behalf of obscure insider editorial theories. Reify-tech (talk) 13:54, 16 March 2020 (UTC)

We seem to have a different definition of idiosyncratic. Let's see if there are other opinions. Klbrain (talk) 01:27, 17 March 2020 (UTC)