[net.micro.cbm] Flames Re: "Valid" AMIGA info.

henry@utzoo.UUCP (Henry Spencer) (06/19/85)

***FLAME WARNING***  Those who are easily singed should read no further.

> ... It will also come  with
> one built-in 3 1/2" disk  drive,  with
> an  approximate  capacity   of   800K.
> ...
> There  is  no
> hard disk as of yet, but third parties
> will  no  doubt  jump  in...

I've thought for some time that the first outfit with a Mac-ish product
that includes a *hard disk* in the standard configuration is going to
clean up.  Evidently the Amiga won't be it, since hard disks aren't
considered important enough to even be available!  Some of us have known
for a decade that storing your data on floppies is like running with
one foot in a bucket.  Having a hard disk always there would do wonders
in eliminating some of the sludge found in micro "operating systems".

> ...   Those  of  you   who   are
> starting to foam at  the  mouth  about
> the mouse should  stop  it  right  now
> (you look silly).  YOU DON'T?
>  HAVE TO USE THE  MOUSE.   The  cursor
> control  keys  will  move  the   mouse
> pointer, and all mouse  functions  can
> be  accomplished  from  the   KEYBOARD
> (which also has  ten  function  keys).

What would make me foam at the mouth is the prospect of using a system
whose mouse has been crippled by the requirement of making it backward
compatible with a keyboard.  Has it escaped these people's attention
that using cursor keys *also* requires moving one hand away from the
home position?

>    But   who   needs   sprites

My sentiments exactly.  They're a vestige of the computer game market;
the silicon/board real estate spent on them is wasted.

> Since a lot of the  graphics  is  done
> using dedicated  hardware,  its  FAST.
> There are features like hardware  line
> drawing and filling (you just tell  it
> where  to  draw  the  line,  with   no
> tiresome calcuations of each point  on
> the line).

Just as important as it being fast is getting it RIGHT.  I wonder if it
handles all the troublesome cases correctly?  I also wonder just how
flexible this hardware is.  Not that it's impossible to do it right,
just non-trivial.

>     One of the nicest features of  the
> graphics hardware is that it uses  the
> "off-phase"  periods  of  the   system
> clock, when the processor is not using
> the  bus.

This is really interesting, since the 68000 *has* no "off phase", unlike
the Motorola 8-bit chips.  In fact, the 68000 is pretty much bus-bound,
and there isn't a lot of spare bandwidth to go around.  There is a smell
of snake oil in the air...

> sound and i/o for the most  part  run
> in the background, without  taking  up
> any processor time at all.   When  the
> processor tells the graphics  chip  to
> draw  a  line  or  fill  a  shape,  it
> doesn't have to hang around  and  wait
> for it to get done...
> Likewise, when the  processor  request
> disk access, the DMA controller  takes
> over...

On a machine as bus-intensive as the 68000, hardware that also wants the
bus is definitely going to slow the cpu down substantially.  Maybe not as
much as if the cpu were doing the work, but it won't be trivial.

> (the   DMA
> controller also make for  FAST,  FAST,
> FAST disk access).

Haven't these people ever heard of seek times and rotational latencies?
DMA is not going to do a damn thing about them, and they're the dominant
factor in disk slowness.

> I  was  told  that
> with medium-heavy animation going  on,
> the 68000 would only lose about 5%  of
> its throughput speed.

I have this bridge to sell you...

> ...   On   the   Amiga,
> practically  every  graphics   feature
> that you can think of is part  of  the
> Operating System, so that the commands
> can be called  by  any  program...

<enter heavy sarcasm mode>
Amazing.  The microcomputer world has discovered the subroutine library,
even if they do insist on calling it "part of the operating system", which
it probably isn't in any strict sense of the term.  If they keep at it,
maybe they'll discover some of the other things the rest of us knew about
fifteen years ago.
<end h.s. mode>

> ...   The  system   has   printer
> drivers  for  graphics  dumps   to   6
> different printers (including  Epsons,
> ink jets, and  color  printers)  BUILT
> INTO (!!!) the OS!


What if my printer isn't one of those six?  Building such things into
the operating system is a *rotten* idea unless there is a way to bypass
it when things change.

> ...  With  the  power
> of the graphics  processor,  virtually
> any kind of complicated  graphics  and
> animation  can  be  accomplished  from
> high  level  languages  like  C   (and
> probably   BASIC)   WITHOUT    MACHINE
> LANGUAGE programming.  ...

Yawn.  What else is new?  Complex graphics and animation are very seldom
written in machine language these days, except in backward parts of the
world (like the microcomputer community).

>      The DOS is not  like  any  other,
> but is said to have "every conceivable
> feature that you could ever think  of,
> and   then   some".

Would it be too much to ask for a simple, small, clean, consistent set of
well-chosen features instead?

> It    supports
> heirarchical directories...
>  The most amazing feature of Intuition
> is that it  is  a  full  MULTI-TASKING
> OS!!!    You   can   have   as    many
> applications  as  memory  will  permit
> RUNNING AT THE SAME TIME...

Those who will not learn from Unix are condemned to re-invent it.  Badly.
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,linus,decvax}!utzoo!henry

skinner@saber.UUCP (Robert Skinner) (06/20/85)

> ***FLAME WARNING***  Those who are easily singed should read no further.
> 
> >     One of the nicest features of  the
> > graphics hardware is that it uses  the
> > "off-phase"  periods  of  the   system
> > clock, when the processor is not using
> > the  bus.
> 
> This is really interesting, since the 68000 *has* no "off phase", unlike
> the Motorola 8-bit chips.  In fact, the 68000 is pretty much bus-bound,
> and there isn't a lot of spare bandwidth to go around.  There is a smell
> of snake oil in the air...
>
You are right that the 68000 has no explicit "off phase", but I wouldn't
call it bus-bound either.  Just because the address lines are active, the 
processor doesn't have to hog memory.

As an example, a couple of companies ago I helped build a graphics terminal
with the 68000 and 640x480 resolution.  60Hz refresh required a pixel rate
of about 28MHz, which implied that we did a 16-bit video read every 570ns.
Now, 570ns is a long time for DRAMS, so we double-buffered the memory, with
280ns (3.5MHz) access cycles and let the video access memory at regular 
intervals with priority.  We put the 68000 clock at 7MHz and it syncs
up to the memory access slot allotted for it.  It's true that the 68000
asserted it's memory lines about half way through the video memory cycle,
but the arbitration logic didn't switch them in until the appropriate time.
So, the two systems co-existed and the 68000 was forced to wait only about
%5 of the time, because very few instructions take a non-multiple of 4 cycles.

I know that 7MHz is not blazing for a vanilla 68K, but 640x480 resolution is
good for a pc.  Of course there are trade offs that can be made:  the clock
speed could be set at 14MHz and video could fetch 32-bit words.  The point is
that 68K systems work with double-buffered memory without *terrible* penalties,
and no snake oil either.

-----------------------------------------------------------------------------
Name:	Robert Skinner
Mail:	Saber Technology, 2381 Bering Drive, San Jose, California 95131
AT&T:	(408) 945-0518, or 945-9600 (mesg. only)
UUCP:	...{decvax,ucbvax}!decwrl!saber!skinner
	...{amd,ihnp4,ittvax}!saber!skinner

matt@ethz.UUCP (Martin Matt) (06/25/85)

>
>> ...   Those  of  you   who   are
>> starting to foam at  the  mouth  about
>> the mouse should  stop  it  right  now
>> (you look silly).  YOU DON'T?
>>  HAVE TO USE THE  MOUSE.   The  cursor
>> control  keys  will  move  the   mouse
>> pointer, and all mouse  functions  can
>> be  accomplished  from  the   KEYBOARD
>> (which also has  ten  function  keys).
>
>What would make me foam at the mouth is the prospect of using a system
>whose mouse has been crippled by the requirement of making it backward
>compatible with a keyboard.  Has it escaped these people's attention
>that using cursor keys *also* requires moving one hand away from the
>home position?


It probably has not escaped those people, but giving the user the choice of
using keyboard or mouse is definitely a good idea. I worked on a Lilith
workstation here at ETHZ and I was often angry about having to use the
mouse to move the cursor up one line.


	Martin Matt (   !cernvax!unizh!vlsivax  )

dimitrov@csd2.UUCP (Isaac Dimitrovsky) (06/27/85)

[]

>> The DOS is not like any other, but is said to have "every conceivable
>> feature that you could ever think of, and then some".
>
> Would it be too much to ask for a simple, small, clean, consistent set of
> well-chosen features instead?

Bravo!!! And ditto for programming languages, having just experienced
the Common Lisp manual.

Isaac Dimitrovsky
allegra!cmcl2!csd2!dimitrov   (l in cmcl2 is letter l not number 1)
251 Mercer Street, New York NY 10012

Just because it's a preconceived notion doesn't mean it's wrong!