shmuel+ibm-m...@patriot.net (Shmuel Metz , Seymour J.) writes: > The 2305-1 and 2305-2 were disks; the drums were 2301 and 2303. Unlike the > drums, the fixed-head disks had[1] 8 exposures and RPS. > > [1] AFAIK the 2305 was the first device to have multiple exposures, > RPS or 2-byte channel connections.
re: http://www.garlic.com/~lynn/2010f.html#65 Mainframe Executive article on the death of tape http://www.garlic.com/~lynn/2010g.html#11 Mainframe Executive article on the death of tape http://www.garlic.com/~lynn/2010g.html#22 Mainframe Executive article on the death of tape http://www.garlic.com/~lynn/2010g.html#24 Mainframe Executive article on the death of tape http://www.garlic.com/~lynn/2010g.html#30 Mainframe Executive article on the death of tape I've mentioned before that the science center had joint project with endicott to support 370 virtual memory architecture ... in cp67 virtual machines. this involved modifying cp67 to add support for "virtual 370" ... as alternative to "virtual 360/67" (aka the format of the tables were different and the control registers were different and some of the instructions were different). Partly because the cambridge cp67 had non-employees (students and others from educational institutions in the cambridge area, aka BU, MIT, Harvard, etc) ... the work went on with a version of cp67 that ran in a 360/67 virtual machine. basically: cp67 "L" ... running on real 360/67 cp67 "H" ... running in virtual 360/67 CP67 "I" ... running in virtual 370 The cp67i system was up and running regularly a year before there was real 370 engineering machine with virtual memory hardware. In fact, the cp67i system was used to test the first engineering 370 with virtual memory hardware (370/145 in endicott). then two engineers from san jose came out and added 3330 & 2305 device support to cp67i ... which was referred to as cp67sj. Then for a long time, there were large number of 370/145s running with the cp67sj system (both before and after 370 virtual memory was announced ... and even after vm370 rewrite was available). as referred to in comments about boeing 3033 and stc electronic paging ... i don't believe they ever got the 2-byte interface working. http://www.garlic.com/~lynn/2010g.html#email800804 370/158 would periodically have issues with just single-byte (1.5mbyte/sec) 2305s ... because of timing, latency and cable length issues ... and 303x channel director was 370/158 engine with just the integrated channel microcode (and w/o the 370 microcode). -- 42yrs virtualization experience (since Jan68), online at home since Mar1970 ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
