Apresentation at SHARE 118 (March 2012) by Dan Greiner, http://comet.lehman.cuny.edu/cocchi/CMP464Mainframe/2.0ZArchitectureLectures/IBMDualAddressSpace.pdf indicates that Dual address space (DAS) support feature was added to the S/370 architecture in 1981. Based on introduction year, thelikely candidates for being first machine with DAS support include later models of 3033, 4381, 3081, 3083, and 3084.
Functional Characteristics of 3084 indicates it has Dual-address space (DAS) as a standard feature, but also lists it as a "3033 extension:" That name seems to confirm that some model of the 3033 was the first with DAS. The introduction year 1981 would explain why a 1979 3033 manual wouldn't mention it. The MVS/SP Release 3 Installation Considerations (July 1981) manual referenced by wmhblair, doesn't mention Dual Address Space support by that name but does describe "3033 Extensions" as an optional microcode feature to support Cross Memory Services in MVS/SP R3in a VM environment. That optional feature was available for 3033 Models A, N, S, U, and M -- not a standard feature, but the 3033 was the first machine for which it was available. Joel C Ewing On 1/3/21 6:39 PM, Joe Monk wrote: > Dual Address Space support is not mentioned anywhere... > > http://www.bitsavers.org/pdf/ibm/3033/GA22-7060-3_3033_FuncChar_Jan79.pdf > > Joe > > On Sun, Jan 3, 2021 at 4:14 PM WILLIAM H BLAIR <[email protected]> wrote: > >> | Does anybody remember the first models to support >> | Dual Address Space for MVS/SP Version 1? I'd like >> | to add that to the wiki [[IBM System/370]] article. >> >> In hardware, it was the 3033 (as well as the 3042 Attached Processor), as >> well as a hardware assist MES for the 3031. It was also, of course, also >> supported on the 3081 (and all processor models thereafter).If I remember >> correctly, this support was not offered for the 3032 in any form. >> >> For additional information, refer to: >> http://www.computinghistory.org.uk/downloads/8823 >> on page 114. >> >> In software, it was supported on any System/370. The ABENDs were >> intercepted by FLIH and the unsupported instructions and control registers >> emulated. >> >> This worked on my 370/158 at the time (1980). >> >> -- >> William Blair >> Sugar Land TX >> ... -- Joel C. Ewing ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
