Re: Why was VAX abandonned ?

From: Paul Sture (nospam_at_sture.homeip.net)
Date: 02/10/04 

Date: Tue, 10 Feb 2004 08:12:00 +0100

Daryl Jones wrote:
>
> glen herrmannsfeldt <gah@ugcs.caltech.edu> wrote in message news:<chFVb.208883$nt4.986971@attbi_s51>...
> > Daryl Jones wrote:
> >
> > (snip)
> >
> > > I don't know everything about IBM systems. You can stop a CPU on a VAX
> > > or Alpha from the console by issuing a control-p, which will produce
> > > the three chevrons >>>. The system will be stop. You can issue a
> > > "continue" and the system will continue were it stop at. There is a
> > > time limit and how much time you have I don't know.
> >
> > IBM S/360 and successors have a PSW bit called WAIT.
> >
> > When set, no instructions are executed, hopefully with
> > interrupts enabled. There is no NULL job or NULL task.
> >
> > The is especially useful when running on a virtual machine,
> > as VM doesn't have to use up 100% of its time running a NULL
> > task loop.
> >
> > The real reason is that IBM used to rent machines, such that the
> > rental charge was based on time actually spent processing.
> > A hardware timer could measure the amount actually used.
> >
> > As far as I know, DEC never rented VAX or Alpha that way.
> >
> > -- glen
>
> Dear Glen Herrmannsfeldt:
>
> I should have said: "I don't know anything about IBM".
>
> There were businesses that rented time out on a VAX/VMS. However, you
> can't charge by cpu runtime. You have to charge by connect time. This
> is due to the runtime not being the same each time the process is
> executed. The difference really showed itself when a process ran with
> no load on the VAX and then on a loaded VAX. This is due to the VMS
> scheduler.
>

Going back 20 years and more, that was always a problem for mainframers
coming to VMS. They had been used to charging usage out to other
departments according to CPU, I/O and disk usage, but VMS made it
difficult to pin CPU and I/O usage down the same way, especially when
using a single process to service requests for multiple users. 

-- 
Paul Sture

Relevant Pages

  • Re: A whopping 50 percent... ???
    ... With VAX and Alpha under the control of the same company ... >>providing VMS there has never been an issue with VMS losing the ... >>of VMS depends upon whoever makes the CPU. ... There are people still running VAX ...
    (comp.os.vms)
  • Re: Does a Repair Install Affect Performance?
    ... I downloaded and ran ccleaner. ... CPU shot up to 80%+ for about 12 seconds while it started. ... image name producing the high CPU usage, right click, ... Yes it is a Dell - a Dimension 4600 installed December 2004. ...
    (microsoft.public.windowsxp.perform_maintain)
  • Re: CPU Pegged at 100%
    ... So, the system appears to be clean, and yet a huge amount of cpu appears to ... Did you disable McAfee and Windows Defender before running Housecall? ... Even when a programme with a memory leak is ... You can check pagefile usage more directly using pagefilemon. ...
    (microsoft.public.windowsxp.perform_maintain)
  • RE: Taskmgr using more CPU time than normal
    ... I understand that the task manager used 15-30% CPU ... CPU usage is related with many factors, ... Test in Clean Boot environment ... Windows XP can still be used in Windows 2000. ...
    (microsoft.public.windows.server.sbs)
  • Re: VAX 4000/500 general questions
    ... SHOW LICENSE ... and talk to VMS. ... You wrote that you connected the VAX directly to the PC. ... will tell you how many disks are present in the system. ...
    (comp.sys.dec)
Loading