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The IBM System/360: the first modular, general-purpose computer

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Re: The IBM System/360: the first modular, general-purpose computer

#11

Post by minipci1321 »

Sanddancer wrote: post #7
digi_owl wrote: post #4

Earlier quoted context omitted.

Not sure if it was the IBM drives or similar designs from other companies, but apparently if you abused the drive just right (it could be controlled completely by software) you could make it walk across the floor. Some university IT labs held late night HDD races...

Lots of tape drives from that era could do that. You've got big heavy motors and spindles, which means lots of inertia. Tell a drive to spin up to full speed, then abruptly stop, and you got lots of angular momentum that still needs to be dissipated. As the spindle assembly is anchored to the chassis, this ends up getting dissipated through the chassis as a quick movement. Spool up the spindles in the opposite direct…

> and then abruptly stop

These were first computers I was exposed to. As students and later young engineers working with them, we were taught an important principle: "nothing you can do in software can break the hardware". Imagine then my bewilderment when, working with a tape and having some strange-looking "Attention required", I went down to the ceiling only to see the tape still on reels but cut in two pieces.

Re: The IBM System/360: the first modular, general-purpose computer

#13

Post by dalke »

beliu wrote: post #8
gist wrote: post #5

I'd love to see the original authoritative source that the IBM 360 project cost 5 billion in 1960 dollars. Something about that seems way overstated. I am wondering if it's just one of those facts that has been repeated so long that it's just taken for granted as being correct. 5 Billion appears to well exceed the cost to develop the Boeing 747 which was a massive bet the company undertaking.

Author of the post here, thanks for reading! Here's a source citing the $5B figure: http://www-03.ibm.com/ibm/history/ibm100/us/en/icons/system3...

That $5B appears to be the cost of the entire project, including production.

In your essay, you wrote "development cost". Is that meant to include production? Because it appears the development cost as its own line item was no more than $1B.

Have you read Wise's Fortune article to confirm that it says what you think it does? I haven't been able to find it online.

Also, I think it's interesting that nearly all of the sources I found cite that Fortune article, and not an IBM publication. Even an IBM site prefers to quote Fortune instead of their own sources.

Re: The IBM System/360: the first modular, general-purpose computer

#14

Post by clifanatic »

dalke wrote: post #9
gist wrote: post #5

I'd love to see the original authoritative source that the IBM 360 project cost 5 billion in 1960 dollars. Something about that seems way overstated. I am wondering if it's just one of those facts that has been repeated so long that it's just taken for granted as being correct. 5 Billion appears to well exceed the cost to develop the Boeing 747 which was a massive bet the company undertaking.

https://books.google.com/books?id=oaBOuo4mId8C&pg=PA189&dq=I... says: > Estimates of the total cost of System/360 range from $4 to $5 billion. Of this amount, $500 million to $1 billion was development cost, while the rest was used to expand manufacturing capacity and to produce rental machines. The references are Wise (1966b), Evans (1983 p.44), and IBM Annual Reports for 1965 and 1966. Wise (1966b) is a Fortune art…

> Fortune article titled "IBM's $5,000,000 gamble".

I think you're missing some 0's there.

Re: The IBM System/360: the first modular, general-purpose computer

#15

Post by dalke »

clifanatic wrote: post #14
dalke wrote: post #9

Earlier quoted context omitted.

https://books.google.com/books?id=oaBOuo4mId8C&pg=PA189&dq=I... says: > Estimates of the total cost of System/360 range from $4 to $5 billion. Of this amount, $500 million to $1 billion was development cost, while the rest was used to expand manufacturing capacity and to produce rental machines. The references are Wise (1966b), Evans (1983 p.44), and IBM Annual Reports for 1965 and 1966. Wise (1966b) is a Fortune art…

> Fortune article titled "IBM's $5,000,000 gamble". I think you're missing some 0's there.

Oops! Yes. I'll edit my original. Thanks! (No copy&paste from Google Books views.)

Re: The IBM System/360: the first modular, general-purpose computer

#16

Post by cpr »

DonaldFisk wrote: post #12

It was preceded by the more advanced Burroughs B5000, which had a stack-based architecture, was directly programmable in Algol60, and had virtual memory.

Not to nit-pick but it was Burrough's Algol systems programming dialect rather than straight Algol60. Damned impressive, yep. (See Alan Kay's various talks about computer history.)

Re: The IBM System/360: the first modular, general-purpose computer

#17

Post by dzdt »

minipci1321 wrote: post #11
Sanddancer wrote: post #7

Earlier quoted context omitted.

Lots of tape drives from that era could do that. You've got big heavy motors and spindles, which means lots of inertia. Tell a drive to spin up to full speed, then abruptly stop, and you got lots of angular momentum that still needs to be dissipated. As the spindle assembly is anchored to the chassis, this ends up getting dissipated through the chassis as a quick movement. Spool up the spindles in the opposite direct…

> and then abruptly stop These were first computers I was exposed to. As students and later young engineers working with them, we were taught an important principle: "nothing you can do in software can break the hardware". Imagine then my bewilderment when, working with a tape and having some strange-looking "Attention required", I went down to the ceiling only to see the tape still on reels but cut in two pieces.

Its funny. In the early days of consumer PC's the feeling was very much the opposite. There were persistent rumors of "killer poke" commands (some of which were at least partially true) where an incorrect software command could destroy the hardware.

Re: The IBM System/360: the first modular, general-purpose computer

#18

Post by emersonrsantos »

You can run bare bones OS/360 using hercules-390 [1], which emulates old and new mainframe architectures.

You can play with OS/360 versions like MFT and MVT, read source code (or try!), do a system generation (recompile the "kernel") and run ita facilities.

Hercules-390 has a very active community [2].

PS: OS/360 and many other older IBM systems are now public domain and have almost all source code available.

[1] http://www.hercules-390.eu

[2] http://groups.yahoo.com/group/bercules-390

Re: The IBM System/360: the first modular, general-purpose computer

#19

Post by tolle »

gist wrote: post #5

I'd love to see the original authoritative source that the IBM 360 project cost 5 billion in 1960 dollars. Something about that seems way overstated. I am wondering if it's just one of those facts that has been repeated so long that it's just taken for granted as being correct. 5 Billion appears to well exceed the cost to develop the Boeing 747 which was a massive bet the company undertaking.

But I think it's safe to say that the gamble paid off!

Re: The IBM System/360: the first modular, general-purpose computer

#20

Post by minipci1321 »

dzdt wrote: post #17
minipci1321 wrote: post #11

Earlier quoted context omitted.

> and then abruptly stop These were first computers I was exposed to. As students and later young engineers working with them, we were taught an important principle: "nothing you can do in software can break the hardware". Imagine then my bewilderment when, working with a tape and having some strange-looking "Attention required", I went down to the ceiling only to see the tape still on reels but cut in two pieces.

Its funny. In the early days of consumer PC's the feeling was very much the opposite. There were persistent rumors of "killer poke" commands (some of which were at least partially true) where an incorrect software command could destroy the hardware.

I am not sure whether that principle they taught us was holding 100% of the time, but it for sure helped -- we were fearless ;-). I must say I am glad that I started my developer career by doing systems programming in IBM OSes. It felt like officiating in a temple at the time and age. Compared to channel programming and starting I/O asynchronously, twiddling bits in some register on a PC in a loop on main (and only) CPU felt just wrong to me ;-). Who knew...
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