31–39 of 39 posts
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] htt…
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…
Earlier quoted context omitted.
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.
Commodore computers were particularly susceptible to these. There was a famous one for the PET which could blow out the CRT. I'm also pretty sure I accidentally killed at least one VIC-20 with another, more different poke...
Earlier quoted context omitted.
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.
Commodore computers were particularly susceptible to these. There was a famous one for the PET which could blow out the CRT. I'm also pretty sure I accidentally killed at least one VIC-20 with another, more different poke...
This was roughly the same time the ANSI committee was trying to standardize ASCII. IBM was a proponent of ASCII, but they had shipping deadlines, and kept with their own character set rather than delay while they created ASCII peripherals. The 360 became popular and a lot of code was written for it which assumed the EBCDIC character set (or was it still BCDIC?) was being used, so future mainframes stayed EBCDIC to gr…
http://docklandsljc.uk/2016/06/unicode-cuddly-application-se...
The BCD part is "binary coded decimal" - a way of representing numbers as decimal coded digits, so 0001 1000 meant "18".
The BCD Interchange code was a 6 but character set that allowed the standard encoding of uppercase letters and numbers. It was realised onto punched cards by utilising "digits" 11 and 12.
The extended binary decimal interchange code was a larger space (8-bit) that allowed the encoding of both uppercase and lower case letters.
Incidentally, the terms "upper case" and "lower case" come from printing presses where the individual letter punches (think the head of a typewriter) were stored in "cases" - actually a wooden storage drawer with lots of small rectangular components containing many of each letter; more for E and other vowels, less for Z and X - and since typesetting text involves more lower case than upper case (as per this post) the lower case letters were stored in the lower case so that they would be easier to reach, with the capitals being stored above and sightly further away.
My uncle had one if these in his hanger, amongst helicopter parts. This was the early 80's and he probably picked it up for scrap value from a military surplus sale. As a kid, would always pester him about getting it running. It had large 5 MB disk packs you'd insert into a washing machine sized drive.
Sounds like a cool uncle
"Modular" is a very confusing word to use in the title, since IBM's earlier computers were made from modules. IBM even called the cards in its 1950s-1960 computers "Standard Modular System" (SMS) cards. I think what "modular" is alluding to in the title is that the 360 introduced a whole line of compatible computers, rather than making each computer a separate architecture as had been previous practice. In other word…
Not just component-wise upgradability or ease of assembly, but rather eliminating entirely the concept of doing one-off "integrations" to create new products in the line. In other words, doing with their computer parts what IKEA does with furniture parts: designing and manufacturing only at the component level, then feeding all the finished components into a shared pool of resources, where products are then simple assemblies of resources from the pool.
"Modular" is a very confusing word to use in the title, since IBM's earlier computers were made from modules. IBM even called the cards in its 1950s-1960 computers "Standard Modular System" (SMS) cards. I think what "modular" is alluding to in the title is that the 360 introduced a whole line of compatible computers, rather than making each computer a separate architecture as had been previous practice. In other word…
Did they perhaps mean "modular" in the sense of the computer being composed out of a set of standardized modules, with none of the modules having been constructed for that computer alone? Not just component-wise upgradability or ease of assembly, but rather eliminating entirely the concept of doing one-off "integrations" to create new products in the line. In other words, doing with their computer parts what IKEA doe…