gahe...@gmail.com (George Henke) writes: > I believe IBM produced a pc with a 370 to run VM on a PC. Merrill Lynch > had one. Somewhere in the late 80's I believe.
re: http://www.garlic.com/~lynn/2012l.html#72 zEC12, and previous generations, "why?" type question - GPU computing 1984, xt/370 ... later same board was made available on at as at/370. basically a couple M68k executing subset of vm370 ... code-named washington. it didn't support i/o ... so vm370 was modified to communicate with a monitor running under dos on the 8088 for all i/o functions. it provided approx. 100kip 370 with 384kbytes of memory ... little bit faster than 370/115. however, since all disk i/o (paging, cms file, etc) was being done on 100ms (per block) dos hard disk. By that time, vm370 and cms had gotten quite a bit bloated ... much larger than cp67/cms that would run on 256kbyte 360/67. Also any kind of disk i/o (paging, file activity) could become extremely painful ... compared to what one was use to with real mainframe disks. I got con'ed into doing some work on it ... first thing simple paging tests showed almost any cms application would page thrash in the pageable pages available left over after vm370 kernel fixed storage size (from 384kbytes) ... exhaserbated by the paging on dos xt disk. I got blamed for several month schedule ship in the product while they upgraded the memory from 384kbytes to 512kbytes ... to cut down on severe paging problems. However, cms applications that tended to be much more file intensive than (and fared poorly in comparison with) equivalent applications developed for the DOS/XT resource limited environment. I had tried to start a project to implement a super lean and fast vm370 replacement kernel in pascal. As a demo I had re-implemented the vm370 kernel spooling function in pascal running in virtual address space. My objective was to enormously increase the throughput and performance compared to the kernel assembler implemented equivalent. I had another agenda ... I was also doing high-speed data transport project ... and for vm370 vnet ... which was dependent on vm370 spool ... I needed multi-megabyte sustained thruput to drive the links I had. misc. past posts mentioning hsdt http://www.garlic.com/~lynn/subnetwork.html#hsdt I indirectly referenced it in previous post regarding work with NSF on what was to become NSFNET backbone ... also original mainframe tcp/ip product was done for vm370 in pascal ... and I did the rfc1044 enhancements that got sustained channel thruput (between 4341 and cray machine using only modest amount of 4341 processor, about 500 times improvement in bytes moved per instruction executed). misc. past posts mentioning NSFNET backbone http://www.garlic.com/~lynn/subnetwork.html#nsfnet -- virtualization experience starting Jan1968, online at home since Mar1970 ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
