[SIGCIS-Members] Candidate World Records -- Biggest Hard Drive, Tape and Portable Computer

[Allan Olley]

Hello,

So just to attempt to clarify how big the SSEC tape drive was. I've 
discussed this with Tom and admitted much confusion looked about started 
to see answers and then never nailed anything down, so let me just do 
this now.

Anyway I am very sure the actual reels of paper tape used on the SSEC were 
much smaller than the 400 pounds of tape stock delivered fromt the 
factory. A 400 pound paper tape would have stored I am guessing about 25 
times as many numbers on the tape then the contemporary accounts refer to 
as stored by the machine in total. The standard size of the tapes was 
probably more like 15 pounds of paper for all tapes on the machine and so 
slightly less than 5 pounds for each large tape on the main readers. They 
were certainly still very bulky and just looking at pictures of them I 
would guess they weighed somehting like 20 pounds, so I am still confused. 
Anyway my logic and evidence for these statements goes as follows (much 
unnecessary detail follows):

So each number on the tape was coded in a row (78 potential punches) in 
binary-coded decimal (4 bits to the digit) 19 digits plus sign (so some 
descriptions of the SSEC describe it as using numbers of 19 digits, others 
as 20).

For comparison a standard IBM punch card was 80 columns, 10 rows of digits 
0-9 and two invisible rows (A, B or X, Y).

Contemporary accounts (Wallace Eckert, "Electrons and Computation" in The 
Scientific Monthly, Vol 67, No 5 (Nov) 1948 pp. 315-323) say the three 
main tape drives of the SSEC store in total 20 000 numbers or 6 666 
numbers on each tape drive. 12 numbers are 12 rows and so constitue ~1 
punch card, so each main tape drive has the equivalent paper of 
~556 punch cards or ~1666 cards worth of paper in total. An IBM 
carrynig case for 2000 cards apparently weighed 6.6 kg (14.52 lbs) 
according to this webpage https://nuhc.ncl.ac.uk/moca/iomedia/pc.htm and 
that sounds about right for the weight of 2 000 cards but I wish I had a 
more definite benchmark to use for the rest of my arithmetic then this 
one number pulled from a random webpage. Anyway, give that I don't think 
the tape on all three tape drives weighed more than 15 pounds, the tape 
on each one would have weighed a little less than 5 pounds.

As mentioned there are 36 tape readers that are associated with 5 000 more 
stored numbers on tape. So each loop contained about 139 numbers (I've 
found archival sources that suggest they sometimes used loops of over 500 
numbers in these configurations but I guess that was non-standard?) tha is 
again rows of tape, so was equivalent to a little more than 10 punched 
cards. So all 36 loops add less than the equivalent of 417 cards, so less 
than another 5 pounds, to the weight of the tapes on the SSEC.

So the 25 000 numbers stored (as standard) on all the SSEC's paper tape is 
just a tad more (1/24th more) paper than 2 000 punched cards in the 
carrying case I am using as my weight unit (which would store 24 000 
numbers by that method). Suggesting the paper tape of the machine 
amounted to about 7 kg of paper or about 15 pounds in total. I 
am not sure you really needed a chain hoist for that, but depending on 
what you are doing with the original 400 poounds of raw paper tape 
received from the factory to prepare it for use, the chain hoist could 
have been useful.

On some subsidiary issues:

If you want to see what the short loops of paper tape looked like there is 
footage of the SSEC available on the Comptuer History Museum's website 
Youtube channel (see 49:50 of https://youtu.be/qundvme1Tik note this 
portion of the video is a lecture given by Herb Grosch). You can see a 
good image of the main paper tape drives at the back of the SSEC in a 
famous of image of the SSEC where the pesky support beams for the room it 
is in have been removed that shows up around 50:25 into the video. They 
are pretty big I don't think big enough to way 400 pounds (or even 133 
pounds each) but big enough that I think they would weigh more than 5 
pounds (they look like more than 500 punched cards worth of paper), I 
would guess 15 or 20 pounds (so each tape is more than 2000 cards worth of 
paper).

I am pretty sure the reels on the main tape readers are glued together at 
the end into a continous loop because John Backus describes an incident 
where the SSEC started to act strangely and they realized they had glued 
the ends of the tape together the wrong way around creating a giant mobius 
strip of tape (and so reversing the numeric encoding of instructions and 
data at various points). I can't imagine you would not notice if the short 
loops of tape were a mobius strip basically as you hung them up, so it 
must of have been one of the three master tapes and so they must operate 
as continuous loops at least some of the time.

(Backus's memory of this comes from page 126 of The History of Computing 
in the Twentieth Century, ed. Nicholas Metropolis, J. Howlett and 
Gian-Carlo Rota, 1980 Academic Press, 
https://books.google.ca/books?id=AsvSBQAAQBAJ&lpg=PA126&ots=Xgj6NX9t4_&dq=Mobius%20loop%20SSEC%20tape%20Backus&pg=PA126#v=onepage&q=Mobius%20loop%20SSEC%20tape%20Backus&f=false 
but I also have run across descriptions of this process, but not the 
Mobius strip incident, in unpublished material)

-- 
Yours Truly,
Allan Olley, PhD

http://individual.utoronto.ca/fofound/

On Sun, 20 Sep 2020, thomas.haigh at gmail.com wrote:

> 
> Hello SIGCIS,
>
> 
> 
> I have agreed to a fun little consulting job of helping the Guinness World
> Records people update and improve their computer-related records. Although
> the Encyclopedia Britannica and other traditional authorities have fallen
> by the wayside, the records book is still going strong and is perhaps the
> last published authority standing. Also, somebody once tried to prove me
> wrong by invoking it. So now I can make sure that doesn’t happen again…
>
> 
> 
> I’ll be dribbling out a couple of additional requests over the next week or
> so, not to overwhelm the list. I have some fun candidate records, but would
> like to see if they hold up among this expert body. BTW, If you have an
> idea for a good record feel free to pitch it to me, but to avoid
> overwhelming the list better to send it directly. We are trying to avoid
> firsts, which have traditionally accounted for the majority of the
> computer-related records.
>
> 
> 
> BIGGEST HARD DISK: First up, the biggest hard disk. Not the largest
> capacity, the BIGGEST. I figure records like that will illustrate better
> than finding some boring box with a high capacity, and are less likely to
> be out of date by the time the book is published. Plus where do you draw
> the line between a drive and an array?
>
> 
> 
> Everyone knows RAMAC, which apparently had 24 inch platters. Platters
> generally shrank over the years, as everything else being equal smaller
> platters can be spun faster, so I believe later mainstream IBM systems were
> smaller. But third parties offered higher performance, higher capacity
> drives. The best candidate appears to be the Bryant Model 2 Disk File from
> the early 1960s. That had 39 inch platters. The image below is from a
> brochure online at CHM:https://archive.computerhistory.org/resources/text/Bryant/Bryant.Model2.19
> 65.102646212.pdf.
>
> 
> 
> [IMAGE]
>
> 
> 
> According to Wikipedia, “Also in 1961, Bryant Computer Products introduced
> its 4000 series disk drives. These massive units stood 52 inches (1.3 m)
> tall, 70 inches (1.8 m) long, and 70 inches (1.8 m) wide, and had up to 26
> platters, each 39 inches (0.99 m) in diameter, rotating at up to 1,200
> rpm.” This Computer History Museum page seems to be hedging bets by calling
> the Bryant units “among the physically largest drives everbuilt”: https://www.computerhistory.org/storageengine/hdd-competitors-ente
> r-the-market/
>
> 
> 
> I’m fairly sure that the Bryant platters were the largest in a standard
> commercial product. Can anyone prove differently? Or know of a
> special-purpose system with even larger platters?
>
> 
> 
> BONUS – HEAVIEST TAPE REEL: I am pretty sure that the IBM SSEC had the
> heaviest tape reel, at 400 pounds, which was a roll of the paper stock
> cards were cut from. I believe this was run in an endless loop to used as a
> high speed lookup table. It had to be lifted with a special mechanism. But
> if anyone knows of a bulkier tape, let me know. The SSEC tape is documented
> at http://www.columbia.edu/cu/computinghistory/ssec-tape.html. That
> includes this description from Herb Grosch:
>
> 
> 
> "About those tapes: the card plant in Endicott got enormous rolls of card
> stock from the paper mills. For regular card manufacturing they slit the
> rolls to three-inch width (card height). For the SSEC they furnished rolls
> eight inches wide (card length). The resulting rolls weighed 400 pounds,
> and had to be hoisted onto the SSEC with a thoughtfully-provided chain
> fall! For the Stallion, we pushed the rolls up a ramp.
> 
> "The punch stations, slightly modified from standard IBM reproducer
> components, punched two round sprocket holes at the edges, and 78(!)
> regular IBM rectangular holes in between. The sprockets drove the tape one
> line at a time, and drives under separate program control fed the fresh or
> pre-punched tape under ten 78-brush reading stations. The tapes hanging
> down could lengthen and shorten, and for program tapes and the table lookup
> unit we cemented the tape end-to-end into short loops (yes, someone had had
> to provide the jig). There were three of these monsters at the end of the
> machine room. Up to 36 of the fixed-length tape loops could be mounted on
> the separate table-lookup unit, which in later years was also sometimes
> used for program reading. For the lunar calculation, I used 24 loops to
> make lookup time as short as possible, and we got programming from the main
> tape readers."
>
> 
> 
> BONUS – LARGEST PORTABLE COMPUTER
>
> 
> 
> That appears to be DYSEAC, which makes sense as AFAIK it was the only
> portable full-scale vacuum tube computer. It apparently weighed 20 tons and
> took two 40 foot trailers to move. (Weight includes the trailers, but not
> the tractors to pull them). I asked Evan Koblentz, who wrote a book about
> portable computers, and he couldn’t think of a heavier/larger one. This
> makes even the Osbourne and IBM PC Portable look extremely light. Read
> about the DYSEAC here:
> http://ed-thelen.org/comp-hist/SEAC&DYSEAC-3-150.pdf, including this image:
>
> 
> 
> [IMAGE]
>
> 
>
> 
> 
> It would be fun if official recognition of these records prompted some
> enterprising teams to attempt to beat them.
>
> 
> 
> Best wishes,
>
> 
> 
> Tom
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