11 ms·

Building the System/360 Mainframe Nearly Destroyed IBM

87 points by headalgorithm 8y ago

IndrekR 8y ago
The Mythical Man Month is a great collection of essays by Fred Brooks, written about his experience in development of the OS/360 for this iron. Parts of it are still very relevant for the engineers today. * https://en.wikipedia.org/wiki/The_Mythical_Man-Month https://en.wikipedia.org/wiki/The_Mythical_Man-Month
- maerF0x0 8y ago
  In your opinion what parts?
  - segmondy 8y ago
    Well, to tell you how useful the book is. I own 3 copies and keep them by my desk. When people ask why I tell them so I can read it 3x faster.
- flukus 8y ago
  It's amazing how much of it would describe a modern agile team but on the other hand there's still some largely unexplored territory. Last year I got to spend a lot of time working in a team of two that was much like the surgical team approach, the c++ expert cranked out code while I as the linux expert (the closest we had anyway) cleared the path, got the environment, builds, source control and scripts to work. Having a specialized tool maker doesn't seem very common either, it seems like in most places everyone is there own toolmaker with little to no sharing, or that there are no toolmakers.
dmckeon 8y ago
> In the first month following the S/360 announcement, customers worldwide ordered over 100,000 systems. Orders equal to 5 times the installed base in US, US, EU, and JP, at a development cost of $50k/order [5 billion $/100k orders = 50k in 1965 USD, ~400k in 2019 USD]. From a software perspective, Brooks’ book was educational, but from a business perspective, the order numbers are inspiring.
- lucas_membrane 8y ago
  > over 100,000 systems Where did that number come from? How many were model 20's? That would be 100 mainframes for each company in the Fortune 1000. How many of the 100,000 were installed and paid for? At even a low $50k per machine, that would be almost double IBM's total annual revenue in the mid 1960's, and they sold lots of punch cards, tabulators, sorters, collators, printers, minicomputers (1130's machines would have taken and 1620's, right?), calculating card punches, disk drives, tape drives, data cells, YNI. I toured the IBM mainframe production line at Poughkeepsie in early 1967, and it did not move quickly nor was it a beehive of activity, maybe 5 machines in process, and none of them moved in the 30-60 minutes I was there. I did not get the idea they could churn those things out in the 1000's.
lucas_membrane 8y ago
Article mentions that 1401 emulation on the lower models of the 360 (models 30 and 40, I think), was a key to success of the 360's. I know that emulation also ran later on larger and later models, 370's, etc. Anybody know when this stopped? I recall one company still running 1401 autocoder (on an IBM 3090 or something like it) until Y2k conversion was not feasible. Did any of those old autocoder systems survive past Y2k?
- wahern 8y ago
  The person who wrote this emulator, https://github.com/moshix/IBM1401 https://github.com/moshix/IBM1401, might know.
- GeorgeTirebiter 8y ago
  That original emulation was actually in microcode; and it wasn't quite 100% compatible with all the options and extensions that were possible for the 1401 (example: multiply and divide hardware was optional on the 1401). Seems to me that pure software emulators (like the one written in BAL, mentioned below) would not be subject to any particular kind of Y2K problem. I think it was more of a problem of having very old 'working' legacy code that nobody wanted to touch anymore. If one had the expertise, one could in principle do Y2K fixes to (original) 1401 autocoder code. There is excellent work by Ken Shirriff e.g. http://www.righto.com/2019/01/accounting-machines-ibm-1403-and-why.html http://www.righto.com/2019/01/accounting-machines-ibm-1403-a... that has much 1401 detail.
  - lucas_membrane 8y ago
    >> If one had the expertise, one could in principle do Y2K fixes to (original) 1401 autocoder code << By 1999 there were so many generations of 360 programs that read and wrote the same files as the 1401 code that any changes to record formats (e.g. 4-digit years) would have been very impractical. The worse date rollover for the 1401 code came in April of 1983, when months since 1900 reached 1000. Stuff like that mostly got fixed with overpunches, but some of the record layouts were running out of places to overpunch. I read that page by Ken Shirriff when it was posted somewhere a few weeks ago. Very informative. > multiply and divide hardware was optional on the 1401 Weren't both floating point (wobbly precision) and packed fixed decimal each extra-cost options on the first 360's?
gumby 8y ago
simultaneously launching all those processors and peripherals is the opposite of today's doctrine of "start with a minimum viable product and expand from there"
gumby 8y ago
Check out the photo of the obviously hand-made core memory -- the caption implies it was a production unit. I am not sure if that is correct but the photo above shows how manual the overall assembly was. It's true that back then people were still bonding wires to transistors by hand in Mountain View and Palo Alto, but that approach was already on its way out. From those photos I can see how only 20 years before IBM had been able to retool its factories to make machine guns for WWII. Nowadays such a radical retooling seem inconceivable to me.
- vmh1928 8y ago
  Remember that IBM had a long history building time clocks, card punch / sorter equipment and cash registers. All mechanical devices. Going from that to a device with a few moving parts that shot bullets was not a huge leap.
patrickg_zill 8y ago
They had $750 million worth in inventory before they were able to build and ship their first system. Afterwards they were hiring something like 1000 new people per month...
slfnflctd 8y ago
Utterly riveting for me, so many lessons to unpack here. No summary can do it justice-- if you are at all interested in the history behind the importance of portable software, read the whole thing. I did not realize the extent to which IBM essentially 'bet the farm' on this concept. Fun fact I just learned: some of the software written for these machines can now run alongside Node.js on the same hardware. That's some impressive legacy support.
- abraae 8y ago
  It's also an interesting twist on the Innovator's Dilemma. The lesson IBM CEO Tom Watson took from the project was: > Years later, when asked whether IBM would ever engage in such a massive project again, one executive barked out, “Hell no, never again.” Watson tilted toward a similar reaction. Commenting in 1966, he said, “At our size, we can’t go 100 percent with anything new again,” meaning anything that big. After the 360, Watson made it a policy “never to announce a new technology which will require us to devote more than 25 percent of our production to that technology.” Yet if IBM had had the balls to hold onto that "bet the farm" spirit, then they might not be quite the sad husk of a formerly great company they are today.
  - xref 8y ago
    Or they might have gone bankrupt decades ago :) the problem with betting-the-farm is you’ve gotta win every time, one miss and you’re kaput
    - vmh1928 8y ago
      Yes. There's a bit of survivor bias in this story and a tendency to look back and think the outcome was inevitable. Although, if you look at the story of the PC Division, there are similarities even though the scale and risk are different. Both the S360 and PC were new creations built by empowered teams that addressed issues with existing technology. Standard interfaces and extensibility were a big part of the success of both stories. Not "open" in the sense we use the word today but standardized - the ISA bus allowed the extensibility of the PC via any number of peripherals, just as whatever the cabling spec of the S360 was for disk, tape, card punch, sorting and tabulating equipment. Enabled by software. A lot is made of the hardware story here, it would be interesting to have part of the operating system development story.
ThrowawayR2 8y ago
Always fascinating to read the history behind the giants of early computing history. We tend to forget that IBM was one of the FAANGs of its era, creating systems and technologies that transformed the world before relative newcomers like x86 or UNIX even existed.
- deleted 8y ago
  [deleted]
- rmckayfleming 8y ago
  THE FAANG of its era.
  - jhallenworld 8y ago
    To give an idea, read this 1974 article: https://reason.com/archives/1974/04/01/ibm/print https://reason.com/archives/1974/04/01/ibm/print "the 1956 consent decree (which settled the 1952 suit) placed significant restrictions on IBM's computer business [4], and is responsible for the very existence of some segments of the computer industry. It required that IBM sell its machines as well as lease them—there are now over a hundred firms whose sole business is leasing IBM computers! They buy from IBM, depreciate the machines over a longer lifetime, and charge lower rental fees.[5] (Recently some of these leasing companies have expressed their desire that IBM be forced out of the leasing business altogether.[6]) Another provision of the decree aided the growth of the computer services business. It required that IBM operate its services business as an independent (wholly owned) subsidiary, Service Bureau Corporation (SBC), and that any equipment and services provided for SBC be on the same terms as for any other company. Ironically, as part of the settlement of the CDC suit last year, CDC bought Service Bureau Corporation from IBM, and since CDC is not under any antitrust restrictions, it expects SBC to be much more profitable! [7] The 1956 decree also required IBM to train personnel and provide technical manuals for anyone who owns, repairs, maintains, or distributes IBM electronic data processing equipment. The decree also ordered IBM to grant unrestricted licenses to companies desiring to use its patents, and enjoined IBM from instituting any suits for patent infringement which occurred prior to the date of the decree. The aim of these provisions was to cut IBM's share of the market and to "enhance" competition." At the time, the computer industry was known ato be made up of "snow white and the seven dwarfs": "Snow White was IBM and the seven dwarfs were Burroughs, UNIVAC, NCR, Control Data Corporation, Honeywell, General Electric and RCA"
bogomipz 8y ago
>"In mid-1963, engineers in the Poughkeepsie and Endicott laboratories had begun exploring the possibility of adding special microcode to the control stores of computers to improve their performance when simulating earlier IBM computers.” Does anyone know did IBM invent microcoded control stores then? This is pretty fascinating.
- fanf2 8y ago
  Microcode was invented as part of the EDSAC 2 project at Cambridge University in about 1957. EDSAC 2 was also the first bit-sliced hardware design (which made it easier to replace parts that had failed).
  - bogomipz 8y ago
    Interesting thanks. What is "bit-sliced hardware design"? I am not familiar with this term.

87 points by headalgorithm 8y ago

The Mythical Man Month is a great collection of essays by Fred Brooks, written about his experience in development of the OS/360 for this iron. Parts of it are still very relevant for the engineers today. * https://en.wikipedia.org/wiki/The_Mythical_Man-Month https://en.wikipedia.org/wiki/The_Mythical_Man-Month

maerF0x0 8y ago
In your opinion what parts?
- segmondy 8y ago
  Well, to tell you how useful the book is. I own 3 copies and keep them by my desk. When people ask why I tell them so I can read it 3x faster.
flukus 8y ago
It's amazing how much of it would describe a modern agile team but on the other hand there's still some largely unexplored territory. Last year I got to spend a lot of time working in a team of two that was much like the surgical team approach, the c++ expert cranked out code while I as the linux expert (the closest we had anyway) cleared the path, got the environment, builds, source control and scripts to work. Having a specialized tool maker doesn't seem very common either, it seems like in most places everyone is there own toolmaker with little to no sharing, or that there are no toolmakers.

dmckeon 8y ago

> In the first month following the S/360 announcement, customers worldwide ordered over 100,000 systems. Orders equal to 5 times the installed base in US, US, EU, and JP, at a development cost of $50k/order [5 billion $/100k orders = 50k in 1965 USD, ~400k in 2019 USD]. From a software perspective, Brooks’ book was educational, but from a business perspective, the order numbers are inspiring.

lucas_membrane 8y ago
> over 100,000 systems Where did that number come from? How many were model 20's? That would be 100 mainframes for each company in the Fortune 1000. How many of the 100,000 were installed and paid for? At even a low $50k per machine, that would be almost double IBM's total annual revenue in the mid 1960's, and they sold lots of punch cards, tabulators, sorters, collators, printers, minicomputers (1130's machines would have taken and 1620's, right?), calculating card punches, disk drives, tape drives, data cells, YNI. I toured the IBM mainframe production line at Poughkeepsie in early 1967, and it did not move quickly nor was it a beehive of activity, maybe 5 machines in process, and none of them moved in the 30-60 minutes I was there. I did not get the idea they could churn those things out in the 1000's.

lucas_membrane 8y ago

Article mentions that 1401 emulation on the lower models of the 360 (models 30 and 40, I think), was a key to success of the 360's. I know that emulation also ran later on larger and later models, 370's, etc. Anybody know when this stopped? I recall one company still running 1401 autocoder (on an IBM 3090 or something like it) until Y2k conversion was not feasible. Did any of those old autocoder systems survive past Y2k?

wahern 8y ago
The person who wrote this emulator, https://github.com/moshix/IBM1401 https://github.com/moshix/IBM1401, might know.
GeorgeTirebiter 8y ago
That original emulation was actually in microcode; and it wasn't quite 100% compatible with all the options and extensions that were possible for the 1401 (example: multiply and divide hardware was optional on the 1401). Seems to me that pure software emulators (like the one written in BAL, mentioned below) would not be subject to any particular kind of Y2K problem. I think it was more of a problem of having very old 'working' legacy code that nobody wanted to touch anymore. If one had the expertise, one could in principle do Y2K fixes to (original) 1401 autocoder code. There is excellent work by Ken Shirriff e.g. http://www.righto.com/2019/01/accounting-machines-ibm-1403-and-why.html http://www.righto.com/2019/01/accounting-machines-ibm-1403-a... that has much 1401 detail.
- lucas_membrane 8y ago
  >> If one had the expertise, one could in principle do Y2K fixes to (original) 1401 autocoder code << By 1999 there were so many generations of 360 programs that read and wrote the same files as the 1401 code that any changes to record formats (e.g. 4-digit years) would have been very impractical. The worse date rollover for the 1401 code came in April of 1983, when months since 1900 reached 1000. Stuff like that mostly got fixed with overpunches, but some of the record layouts were running out of places to overpunch. I read that page by Ken Shirriff when it was posted somewhere a few weeks ago. Very informative. > multiply and divide hardware was optional on the 1401 Weren't both floating point (wobbly precision) and packed fixed decimal each extra-cost options on the first 360's?

gumby 8y ago

simultaneously launching all those processors and peripherals is the opposite of today's doctrine of "start with a minimum viable product and expand from there"

gumby 8y ago

Check out the photo of the obviously hand-made core memory -- the caption implies it was a production unit. I am not sure if that is correct but the photo above shows how manual the overall assembly was. It's true that back then people were still bonding wires to transistors by hand in Mountain View and Palo Alto, but that approach was already on its way out. From those photos I can see how only 20 years before IBM had been able to retool its factories to make machine guns for WWII. Nowadays such a radical retooling seem inconceivable to me.

vmh1928 8y ago
Remember that IBM had a long history building time clocks, card punch / sorter equipment and cash registers. All mechanical devices. Going from that to a device with a few moving parts that shot bullets was not a huge leap.

patrickg_zill 8y ago

They had $750 million worth in inventory before they were able to build and ship their first system. Afterwards they were hiring something like 1000 new people per month...

slfnflctd 8y ago

Utterly riveting for me, so many lessons to unpack here. No summary can do it justice-- if you are at all interested in the history behind the importance of portable software, read the whole thing. I did not realize the extent to which IBM essentially 'bet the farm' on this concept. Fun fact I just learned: some of the software written for these machines can now run alongside Node.js on the same hardware. That's some impressive legacy support.

abraae 8y ago
It's also an interesting twist on the Innovator's Dilemma. The lesson IBM CEO Tom Watson took from the project was: > Years later, when asked whether IBM would ever engage in such a massive project again, one executive barked out, “Hell no, never again.” Watson tilted toward a similar reaction. Commenting in 1966, he said, “At our size, we can’t go 100 percent with anything new again,” meaning anything that big. After the 360, Watson made it a policy “never to announce a new technology which will require us to devote more than 25 percent of our production to that technology.” Yet if IBM had had the balls to hold onto that "bet the farm" spirit, then they might not be quite the sad husk of a formerly great company they are today.
- xref 8y ago
  Or they might have gone bankrupt decades ago :) the problem with betting-the-farm is you’ve gotta win every time, one miss and you’re kaput
  - vmh1928 8y ago
    Yes. There's a bit of survivor bias in this story and a tendency to look back and think the outcome was inevitable. Although, if you look at the story of the PC Division, there are similarities even though the scale and risk are different. Both the S360 and PC were new creations built by empowered teams that addressed issues with existing technology. Standard interfaces and extensibility were a big part of the success of both stories. Not "open" in the sense we use the word today but standardized - the ISA bus allowed the extensibility of the PC via any number of peripherals, just as whatever the cabling spec of the S360 was for disk, tape, card punch, sorting and tabulating equipment. Enabled by software. A lot is made of the hardware story here, it would be interesting to have part of the operating system development story.

ThrowawayR2 8y ago

Always fascinating to read the history behind the giants of early computing history. We tend to forget that IBM was one of the FAANGs of its era, creating systems and technologies that transformed the world before relative newcomers like x86 or UNIX even existed.

deleted 8y ago
[deleted]
rmckayfleming 8y ago
THE FAANG of its era.
- jhallenworld 8y ago
  To give an idea, read this 1974 article: https://reason.com/archives/1974/04/01/ibm/print https://reason.com/archives/1974/04/01/ibm/print "the 1956 consent decree (which settled the 1952 suit) placed significant restrictions on IBM's computer business [4], and is responsible for the very existence of some segments of the computer industry. It required that IBM sell its machines as well as lease them—there are now over a hundred firms whose sole business is leasing IBM computers! They buy from IBM, depreciate the machines over a longer lifetime, and charge lower rental fees.[5] (Recently some of these leasing companies have expressed their desire that IBM be forced out of the leasing business altogether.[6]) Another provision of the decree aided the growth of the computer services business. It required that IBM operate its services business as an independent (wholly owned) subsidiary, Service Bureau Corporation (SBC), and that any equipment and services provided for SBC be on the same terms as for any other company. Ironically, as part of the settlement of the CDC suit last year, CDC bought Service Bureau Corporation from IBM, and since CDC is not under any antitrust restrictions, it expects SBC to be much more profitable! [7] The 1956 decree also required IBM to train personnel and provide technical manuals for anyone who owns, repairs, maintains, or distributes IBM electronic data processing equipment. The decree also ordered IBM to grant unrestricted licenses to companies desiring to use its patents, and enjoined IBM from instituting any suits for patent infringement which occurred prior to the date of the decree. The aim of these provisions was to cut IBM's share of the market and to "enhance" competition." At the time, the computer industry was known ato be made up of "snow white and the seven dwarfs": "Snow White was IBM and the seven dwarfs were Burroughs, UNIVAC, NCR, Control Data Corporation, Honeywell, General Electric and RCA"

bogomipz 8y ago

>"In mid-1963, engineers in the Poughkeepsie and Endicott laboratories had begun exploring the possibility of adding special microcode to the control stores of computers to improve their performance when simulating earlier IBM computers.” Does anyone know did IBM invent microcoded control stores then? This is pretty fascinating.

fanf2 8y ago
Microcode was invented as part of the EDSAC 2 project at Cambridge University in about 1957. EDSAC 2 was also the first bit-sliced hardware design (which made it easier to replace parts that had failed).
- bogomipz 8y ago
  Interesting thanks. What is "bit-sliced hardware design"? I am not familiar with this term.