Subject: Mips on vesa

From: Bill Broadley <[email-masked]>
Date: Sun, 25 Jul 1993 04:36:15 -0500 (EDT)

The original mips design seemed to be basically mips+simm slots on ISA bus and
seems to have been dropped because of ISA limitations and board space.

(see previous msg about the commercial version for mips 4k on VESA for $1750)

How about one simpler.  Just a mips chip (whatever we can afford)+cache 
on a vesa card.  As I understand it VESA is basically the pc memory bus.

Running on the VESA bus at 25-33 Mhz will give you 100-128 MB/sec bandwdith
to memory, this makes a local cache important but seems workable.

Everything would be reused.  People could buy the ISE/VESA card of there choice.
A 486/25 sx is $215 or so would be used as a host.

-- 
Bill					1st>	[email-masked]
[email-masked] <2nd 	3rd> 	             [email-masked]
Linux is great.         Bike to live, live to bike.                      PGP-ok

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From: Drew Eckhardt <[email-masked]>
Date: Mon, 26 Jul 1993 01:56:06 -0600

The original mips design seemed to be basically mips+simm slots 

Plus cheap onboard SCSI, serial ports, video, and perhaps ethernet.
    
    on ISA bus and

Not on an ISA bus, but with an ISA bus for people who insist on 
having PC-compatable expansion slots. 

IMHO, it seems to have been postponed because of

1. No suitable DMA/DRAM/peripherial controller is available - 
	the 3730 isn't shipping and the Visual MOM chipset lacks 
	support for slave mode DMA. (Has anyone looked at the 
	NEC chipset?)

2.  The 4200 would be faster, and should be cheaper than the 
	3081.  Availability at this point is questionable.$

3.  In 6-9 months, IDT ships the Orion, an R4000 compatable chip.
	Also faster and cheaper than the 3081.

    on a vesa card.  

It depends on what our goals are. IMHO, we need to clearly define what these
are before getting furthur into the technical aspects of things.

    As I understand it VESA is basically the pc memory bus.

    Everything would be reused.  People could buy the ISE/VESA card of there ch
   oice.
    A 486/25 sx is $215 or so would be used as a host.

For the people who want a "workstation", the motherboard solution
wins hands down.

+ $200 SCSI (You can't buy large IDE drives at any price)
+ $200 video (VRAM based local bus)
+ $50 16550 serial board
+ ethernet ???

Total : $615 + ???

Compared to a motherboard solution of 

+ $90 main board
+ $25 SCSI
+ $20 (serial ports, either one of the integrated chips or a 16552)
+ $100 video (1M, VRAM based (ie, 1152x900x256) $60 for 2M )
+ ethernet ???

Total : $235 + ???

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From: Peter Holzer <[email-masked]>
Date: Mon, 26 Jul 93 14:36:13 MET DST

> having PC-compatable expansion slots. 

No, the original project was indeed, as Bill wrote, to build a card
with a MIPS processor and some memory to put into a PC. This was soon
changed to build a motherboard, however (But you should know that,
Drew. The first mail I got on this list was by Neil answering (among
other things) your claim that there isn't enough real estate on an isa
board).

> 	Also faster and cheaper than the 3081.

It seems so. But this happened only recently, whereas Bill was talking
about a decision made a month ago. But I don't like going back to the
mips+ram-on-a-card idea. I like it even less if its going to be a vesa
card. I have an old 25MHz 386 without vesa. When I buy a new computer
it it will either be a high-end 486 or some RISC workstation. I will
not buy a 486sx just to plug a crippled mips motherboard into it.

	hp

-- 
|    _  | Peter J. Holzer                       | Think of it   |
| |_|_) | Technical University Vienna           | as evolution  |
| | |   | Computer Science/Real-Time Systems    | in action!    |
| __/   | [email-masked]                 |     Tony Rand |

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From: Drew Eckhardt <[email-masked]>
Date: Mon, 26 Jul 1993 07:23:11 -0600

--------

    with a MIPS processor and some memory to put into a PC. 

If we're being pedantic, yes.  However, Neil quickly conceeded that we 
needed a motherboard if we were going to get any performance out of the
system as a whole, and all recent discussions have been about a system
with a mother board.

    mips+ram-on-a-card idea. 

Agreed.  Performance and total system price would be lousy for people 
looking for a workstation/complete system, who seem to be the majority
of the riscy list readers.

    I like it even less if its going to be a vesa card. I have an old 
    25MHz 386 without vesa. When I buy a new computer it it will either be 
    a high-end 486 or some RISC workstation. 

Agreed.  

With the VESA solution, you get a PC with a MIPS CPU, not a workstation 
with reasonable I/O and video.

    I will not buy a 486sx just to plug a crippled mips motherboard into it.

Like I said, the motherboard solution makes the most sense (performance
and price wise) for the people who want a "workstation", ie the majority
of the riscy list readers.

For people wanting a *simple* solution *now* and not in six months, the 
VESA board is the only viable choice.

NEC's 4200 and chipset look like they're happening now and not in six
months, so I'll talk to NEC today and see if I can get some information 
on availability of their 4200 and chipset, as well as technical 
specifications (the Visual MOM chipset sounded great until we got the 
specs that showed it had no slave mode DMA, no variable bus sizing for 
peripherials, etc).

--------

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From: Peter Holzer <[email-masked]>
Date: Mon, 26 Jul 93 15:35:29 MET DST

> system as a whole, and all recent discussions have been about a system

Yup.

Agreed.

> VESA board is the only viable choice.

Well, `now' is probably somewhat too optimistic, but I agree that it
will be completed in a lot less than 6 months, since all the necessary
parts are available, so all we have to do is design it. However, as you
said the majority of the risciers is interested in a workstation. How
many people could live with a vesa board? I certainly can't. I can
however wait for six months or even a year (of course by then there
might be R4000-based workstations available for similar cost).

> specifications .

Hope you get something.

	hp