On Wed, 12 Nov 2003, Hans Franke wrote:
> > > When going for Sinclair and journalists, I always bring up the Z88
> > > at some point. Old guys may remember them (or similar machines),
> > > while younger often think it's a brand new invention,
>
> > Not a fool mistake. IBM recently released a server called a "z800".
> > http://www-1.ibm.com/servers/eserver/zseries/i/zseries800.jpg
>
> Now, that's the modern incarnation of a REAL(tm) Computer.
>
> > no Z80's or Z8000's in it, I believe.
>
> Nop, the zSeries is todays version of a classic /370. The only real
> differnence to its predecessor (ES9000) is a somewhat weired 64 Bit mode
> - I have still no Idea what it is good for. Shure, the address extension
> from 24 to 31 Bit was quite helpful (8 MB user address space became
> quite tight when you already need 3 for your programm and need more
> speed due caching for 3000 concurent users), but above that, I see no
> real need. We got all bells and whistles in our data base engine, but
> still don't use more than a half a gig of mem. And even there the
> address extension of earlier architectures (swaping address spaces in
> and out of a task - aka banking:) was more than enough.
The zSeries didn't come after ES/9000. It came after S/390 which came
after ES/9000.
> I think, the extension was more a marketing thing than anything else.
Have ever tried doing data operations with data aligned to 64-bit
boundaries on a zMachine? The difference in performance is marked. They
do have instruction set additions for that.
BTW, there are z80's in IBM mainframes. Just not anywhere near the CPU
boards.
Peace... Sridhar
Received on Wed Nov 12 2003 - 16:18:15 GMT
