From: kludge@panix.com   
      
   Lawrence D'Oliveiro   wrote:   
   >On Sun, 4 May 2025 10:22:51 -0400 (EDT), Scott Dorsey wrote:   
   >> Lawrence D'Oliveiro   wrote:   
   >>   
   >>>But they do still suffer the latencies from a platform optimized for   
   >>>batch rather than interactive operation, don’t they.   
   >>   
   >> No, this isn't 1965 any longer.  These are realtime transaction   
   >> processing systems.   
   >   
   >No, they are *batch* transaction processing systems. They have file   
   >formats that still emulate the layout of punch cards.   
      
   Yes, there are still 80 column card images in common use, but they are   
   not batch systems under the hood at all.  (Well, MVS still is, but CMS and   
   CICS sure aren't).   
      
   You should check out Martin's "Design of Real-Time Computer Systems"   
   which was written in the early days of SAABRE and other transaction   
   processing systems.   
      
   >> You _can_ run batch stuff on VM/CMS too ...   
   >   
   >Remember what the VM part was for: it was a kludge because CMS wasn't a   
   >proper multiuser OS. So to work around that, each user was given their own   
   >entire virtual machine.   
      
   Yes, that was the idea, but in the end it turned out to be a win instead   
   of a loss.   I wouldn't call it a kludge so much as a deeper sort of   
   timesharing.   
      
   >> The ability to manage I/O load dynamically is a big deal.   
   >   
   >Not on a modern OS like Linux, that just takes it all in its stride.   
      
   Sadly, I wish that were the case, although I will say that the one good   
   thing about systemd is the "quota system" built into it that does allow   
   some crude per-process I/O restrictions in ways that ionice never did.   
   It's certainly getting better.   
   --scott   
   --   
   "C'est un Nagra. C'est suisse, et tres, tres precis."   
      
   --- SoupGate-DOS v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)