[comp.sys.amiga] Where should X concentrate its CPU cycles?

xanthian@zorch.SF-Bay.ORG (Kent Paul Dolan) (10/25/90)

peter@sugar.hackercorp.com (Peter da Silva) writes:

> [...] I'm sure people will find any window system acceptable  if  it's
> what they started with, but  I've  been  spoiled  by  having  the  O/S
> (Server, etc) do it's job for so long that I'm not  about  to  put  up
> with one that expects the application to. Whether it's  MS-DOS  (which
> requires every program to do thir own serial  drivers),  MacOS  (where
> every  program  is  responsible  for  scheduling)  or  X  (where  the
> application is responsible for maintaining display integrity) it seems
> to  me  a  waste  of  time  to  duplicate  functions  needlessly.

To the contrary, this is exactly in line with the move  from  mainframes
to microcomputers. Remember the horrid bottleneck when 20  students  all
logged  onto  a  VAX  11/750?

The common (server) device  is  going  to  be  the  bottleneck,  so  the
appropriate thing to do is to offload as many cpu cycles as possible  to
the client machine. Anything else would lead to _dreadful_  performance.

You pay for this  with  huge  executables  on  the  client,  but  that's
perfectly fine when memory is cheap and cpu  cycles  (especially  shared
ones), as well as network bandwidth  on  a  common  ethernet  are  dear.

This does not at all suggest or support the idea of writing  the  client
software  from  scratch  for  each  application.
                                                           /// It's Amiga
                                                          /// for me:  why
Kent, the man from xanth.                             \\\///   settle for
<xanthian@Zorch.SF-Bay.ORG> <xanthian@well.sf.ca.us>   \XX/  anything less?
--
Convener, comp.sys.amiga grand reorganization.

jmeissen@oregon.oacis.org ( Staff OACIS) (10/26/90)

In article <1990Oct24.221622.3575@zorch.SF-Bay.ORG> xanthian@zorch.SF-Bay.ORG (Kent Paul Dolan) writes:
->peter@sugar.hackercorp.com (Peter da Silva) writes:
->> every  program  is  responsible  for  scheduling)  or  X  (where  the
->> application is responsible for maintaining display integrity) it seems
->> to  me  a  waste  of  time  to  duplicate  functions  needlessly.
->
->To the contrary, this is exactly in line with the move  from  mainframes
->to microcomputers. Remember the horrid bottleneck when 20  students  all
->logged  onto  a  VAX  11/750?
->
->The common (server) device  is  going  to  be  the  bottleneck,  so  the
->appropriate thing to do is to offload as many cpu cycles as possible  to
->the client machine. Anything else would lead to _dreadful_  performance.
->
->You pay for this  with  huge  executables  on  the  client,  but  that's
->perfectly fine when memory is cheap and cpu  cycles  (especially  shared
->ones), as well as network bandwidth  on  a  common  ethernet  are  dear.


But that's EXACTLY the problem with X. Instead of having the device which
actually performs the display function (the server) handle clip regions
and window refreshing, the application is responsible for these things,\
which puts the burden back on the central system running multitudinous
X applications for users at distributed locations. PLUS it has to push
all this data back and forth over the local net, adding to the net load.

Don't confuse window manager with server. In most cases, the X user has
a box configured as a server, tied in to a central system. This distributes
the SERVER's function, while centralizing CLIENT activity. Obviously you
want to off-load as much as possible onto the server!


-- 
John Meissen .............................. Oregon Advanced Computing Institute
jmeissen@oacis.org        (Internet) | "That's the remarkable thing about life;
..!sequent!oacis!jmeissen (UUCP)     |  things are never so bad that they can't
jmeissen                  (BIX)      |  get worse." - Calvin & Hobbes

dlt@locus.com (Dan Taylor) (10/30/90)

jmeissen@oregon.oacis.org ( Staff OACIS) writes:

>In article <1990Oct24.221622.3575@zorch.SF-Bay.ORG> xanthian@zorch.SF-Bay.ORG (Kent Paul Dolan) writes:
>->peter@sugar.hackercorp.com (Peter da Silva) writes:
>->> every  program  is  responsible  for  scheduling)  or  X  (where  the
>->> application is responsible for maintaining display integrity) it seems
>->> to  me  a  waste  of  time  to  duplicate  functions  needlessly.

>But that's EXACTLY the problem with X. Instead of having the device which
>actually performs the display function (the server) handle clip regions
>and window refreshing, the application is responsible for these things,\
>which puts the burden back on the central system running multitudinous
>X applications for users at distributed locations. PLUS it has to push
>all this data back and forth over the local net, adding to the net load.

>-- 
>John Meissen .............................. Oregon Advanced Computing Institute
>jmeissen@oacis.org        (Internet) | "That's the remarkable thing about life;
>..!sequent!oacis!jmeissen (UUCP)     |  things are never so bad that they can't
>jmeissen                  (BIX)      |  get worse." - Calvin & Hobbes

NONSENSE!!!!! Even cheap X-Terminals have at least SOME "backing-store".
This allows the server to "hide" windows and then redisplay them WITHOUT
sending events to client processes.  Given the Amiga's windowing power,
unless the X implementations are REALLY screwed up, there should be excellent
performance up to the point that CHIP memory is consumed.  Even then, FAST
RAM, even disk files, could be used as backing store, ELIMINATING window
refresh, unless the client has changed some data.  No client or network
overhead.  RT_M.
-- 

* Dan Taylor    * The opinions expressed are my own, and in no way *
* dlt@locus.com * reflect those of Locus Computing Corporation.    *