On 11/19/2016 09:56 AM, william degnan wrote: > True, but for all that I have read about the actual use of the /20 > that was not what it was for. IBM used the /20's as a smart terminal > and that kind of thing. The thing in between the mainframe and > something else operating in a remote location, and so on.
The Model 20 could use 2311 disks (model 11 or 12) as well as the 2415 tape drive. And there *was* a disk operating system of sorts: DPS: http://bitsavers.trailing-edge.com/pdf/ibm/360/model20/C24-9006-4_260-20_CtlPgm_Mar69.pdf Even has S/360 type JCL--and note that PL/I is mentioned. Incredible. One wonders how many "loaded" Model 20 systems were deployed. An awful lot were sold as unit-record system replacements. If you had a disk, IBM really tried to squeeze things small. DOS/360, IIRC, could be shoved into a resident with no more than 8KB. Lots of transient phases, though. --Chuck
