🚀 go-pugleaf

In article <1991Aug27.192220.20958@world.std.com> steveo@world.std.com (Steven W Orr) writes:
>We are trying to configure an SCO Unix system running some type of
>IP, (maybe TCP, maybe UPD) to operate at maximum throughput. Our goal
>is to get up to _6_ Megabits/Sec. We realize that we need EISA bus
>machines with 32-bit Ethernet cards to do this. We also realize that
>we will need multiple cards to accomplish this goal. We have no
>problems spending whatever it takes to make this machine as fast as
>possible, given the SCO/[34]86/EISA constraints.
>
>Another important detail is that each computer will be talking over a
>Cisco router with one ethernet card per computer. This way we
>completely eliminate packet collisions.
>
>Does anyone have SCO running with multiple cards? Which cards are you
>running? How many? What's your throughput?
>
>We have been in touch with Racal Interlan. They recommended their
>6510 card. They told us that it has bus mastering and that it is a 16

No, you can have ISA bus masters (eg Adaptec 1542 SCSI) but be aware
they don't always work in all PCs and often have a memory DMA speed limit
around 5.0MBytes/s (which is below what you may want...)

>bit card. Is this not a contradiction in terms? They said it would
>run at 6 Megabits/Sec. All the wisdom so far says that no 16 bit card
>will average over 1/4 Mb/sec.

Not true, the Adaptec 1542 can do sustained SCSI I/O at around 2.5 MBytes/s
to multiple drives (the EISA 1740 board though does much better and
hogs the I/O bus much less).

>
>They also told us about their ES3210 card, which they claim can
>operate at _13_ Megabits/Sec. I thought that the cable can't operate
>faster than 10 Megabits/Sec. Am I missing something? How do I get
>real numbers that will tell me what to expect in the field?

Mmmm, they may be quoting the burst speed from memory to the controller
across the EISA bus. You will be lucky to get over 75% of 10MBits/s
out of Ethernet really.

>
>I don't know how obvious my lack of network expertise is, but if you
>see any questions that I'm not asking, I need to know that also. I'm
>sure I'm not asking everything I need to know.
>
>Many thanks in advance.
>

I think you are asking too much of a timesharing O/S even with an EISA
PC to get sustained 6Mbytes/s. If you only want it for bursts, you
may have better luck.

Or you might want to try using SCSI as a LAN and use 2 EISA SCSI controllers
(in target and initiator mode) to send the data between systems, though
the range will be limited to 25metres for differential SCSI.

Martin Cryer
Unisys Europe Africa
Unix SVR4 Development
Unisys Salt Lake City

All opinions are my own and not those of my employer.