🚀 go-pugleaf

In article <27637@lll-winken.LLNL.GOV>, brooks@maddog.llnl.gov (Eugene Brooks) writes:
> In article <33942@bu-cs.BU.EDU> bzs@bu-cs.BU.EDU (Barry Shein) writes:

> >Mainframes are generally at the top of the line in overall I/O
> >(particularly disk) performance, that's the critical measure.
> Okay, I will bite on this!  Here are elapsed times in seconds for
> the unpacking of a source archive on some representative machines.

> MACHINE and OS				TIME in SEC
> Cray YMP running NLTSS				40
	. . .
> SUN3 WITH DISK SUNOS 4.0.1			2.7

A cray  is  a  "supercomputer",  not  a  mainframe.   It  is  not
optimized  for  I/O, but for vector computation.  Vaxen are often
used as cray front ends.

What you need is figures for a 3090, but there're hard to come by
since  most mainframes run dinosaur OS's that have never heard of
a source archive.  (Programmers tend not to use macros with their
assembler, let alone a high level language.)

Most of the massive I/O bandwidth on mainframes is wasted due  to
stupid  software.   They can copy files at 3 Mbytes/sec, but even
with only one user, editing is faster on a PC. A  mini  can  load
indexed  files  faster  than  DB2 on a mainframe.  I just read an
article  in  Computerworld  about  how  many  data  centers   are
automating  their  operation.   The most popular "automation"?  A
program to ignore the copious messages appearing on  the  console
--   i.e.   the  operator  doesn't  need  to  keep  pressing  the
acknowledge key.

I think that even in I/O bandwidth,  traditional  (three  letter)
mainframes  are about to be overtaken.  A typical system has 12 x
3 Mbyte/sec independent (and intelligent) channels.   This  gives
an   aggregate  throughput  of  288  Mbits/sec.   The  peripheral
controller  Intel  offers  with  the  486  claims  an   aggregate
throughput of 150 Mbits/sec with 8 independent channels.  This is
getting close, and it is certainly not hard to beat a 6 Mips  CPU
these  days.   I  hear  that  the  NeXT  has  a  high  throughput
peripheral chip also.

The micro solution to high throughput  disks  is  not  fast  (and
expensive)  disks,  but  disk  arrays.   By running lots of cheap
disks in parallel you get the throughput of the big jobbers at  a
fraction of the cost.

The fact remains that software, not hardware, is  what  limits  a
computer  system at any price level.  (With a few special purpose
exceptions.)
-- 
Stuart D. Gathman	<stuart@bms-at.uucp>
			<..!{vrdxhq|daitc}!bms-at!stuart>