[email protected] (David Boyes) writes: > What about things like RSCS v1? I think it could run on bare metal in > its early days (morphed later into becoming GCS-dependent in RSCS v2).
Original CPREMOTE ... straight point-to-point might run on bare metal ... but vnet/rscs used for the internal network had a least spool block diagnose ... used VM370 spool file for intermediate storage (store&forward) and transfer on local machine. In the 80s, the CSC co-worker responsible for VNET/RSCS had left IBM and was working on advanced real-time system projects and thot that parts of the dominant industry real-time operating system looked familiar. He compared the real-time system monitor with RSCS monitor and it turned out to be almost line-by-line translation of 370 assembler to "C" ... including all the original comments. The original announcement in 1976 was joint with JES2 NJI. The problem was that mainstream IBM was still having problems adapting to unbundling announcement and charging for application software. Process was forecast at high, middle, low price and price*numbers had to cover deevelopment and support of the product. There was no forecast for NJI that covered cost. On the other hand VNET/RSCS could get away with $30/month. They fiddled the announcement as combined NJI & VNET at $600/month ... where the VNET revenue covered the NJI shortfall. VNET/RSCS had correctly layered ... but NJI intermixed network fields with job control fields. The result was that VNET/RSCS easily supported both NJI drivers and native drivers (that had much higher throughput than NJI drivers). The intermixing of JES2/NJI fields that traffic between different releases of JES2 could crash the host MVS. The internal network was larger than arpanet/internet from just about the beginning until sometime mid-80s ... mostly RSCS/VNET ... with sprinkling of MVS/JES2. NJI implementation came from HASP (the source carried "TUCC" in cols 68-71) and used spare entries in the 255 psuedo device table to define network nodes ... maybe 150-200 max. nodes ... and would trash traffic if either origin or destination nodes weren't locally defined. By the time NJI/VNET shipped to customers, the internal network had passed 255 nodes ... so there issue that JES2 would discard traffic (when it wasn't crashing MVS). Internally, MVS/JES2 were restricted to edge nodes (to minimize trashing traffic) fronted by RSCS/VNET with special NJI driver that could rewrite NJI header information to match the directly connected JES2/NJI release. At the time arpanet/internet had great switch-over to internetworking protocol on 1Jan1983, it had around 100 IMP network nodes with around 255 connected hosts ... while the internal network was rapidly approaching 1000 (which it passed couple months later). http://www.garlic.com/~lynn/subtopic.html#internalnet and http://www.garlic.com/~lynn/submain.html#hasp The corporate sponsored university network used similar RSCS/VNET technology as the internal network https://en.wikipedia.org/wiki/BITNET and http://www.garlic.com/~lynn/subnetwork.html#bitnet but were increasingly being forced to only ship NJI drivers (even tho native drivers had much better performance ... and then later were later being forced to SNA/VTAM (GCS). Inside IBM I had HSDT project http://www.garlic.com/~lynn/subnetwork.html#hsdt in early 80s, starting to support full T1 and faster speed links. This caused lots of problems in the communication group since 37x5 boxes only supported 56kbits/sec. I also had problems with the RSCS 4k block spool file diagnose interface ... since it was syncronous (RSCS didn't execute while diagnose was in operation) ... and with competition from other users of spool file ... RCSC might only get 3-8 4k blocks/sec (12kbytes-30kbytes) ... and I needed aggregate of couple mbytes/sec. I needed asyncronous, non-blocking diagnose interface, and I needed vm370 spool file to do contiguous allocation, read-ahead, write-behind, multi-block, even full track transfers, old mentioning SFS (spool file system rewrite) http://www.garlic.com/~lynn/2005s.html#28 MVCIN instruction After the mid-80s, I was trying to get the internal network backbone enhanced to support T1 & faster-speed links as well as enhanced spool file operation. The communication group then got the backbone meetings restricted to management only ... as part of forcing move to SNA/VTAM ... not letting technical people confuse the issues. recent discussion http://www.garlic.com/~lynn/2017d.html#72 more IBM online systems old email http://www.garlic.com/~lynn/2011e.html#email870204 and then http://www.garlic.com/~lynn/2006x.html#email870302 http://www.garlic.com/~lynn/2011.html#email870306 -- virtualization experience starting Jan1968, online at home since Mar1970 ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
