garyb@gallium.UUCP (Gary Blumenstein) (06/11/89)
I am posting the following message on behalf of my friend, Chris Lukas
of Continental Computer Systems. Yes, I know we can't advertise
on the net, but it was my feeling that this information would be valuable in
and of itself for general interest.
It is directed to all those people who have tried Computone, Anvil,
Digiboard, Stargate, Hostess, or Arnet and have found problems:
-------------------------< begin >-------------------------------------
The Equinox Megaport 24 port card (AT bus) is finally available.
This card is powered by a custom ASIC (application specific IC)
processor designed by Equinox. This processor has been produced by
Equinox for two years and powers thousands of their data switch
modules. In fact, the processor will in the future support all data
switch functions as well as multiport board functions.
This is the only board capable of pushing over 3800 characters per
second out of all of its ports simultaneously. Computone and Anvil,
besides not being able to run UUCP/Telebit, do not achieve an actual
38400 baud. The other boards on the market do even poorer than these
two. At 96 ports in a system (4 boards) the boards can push 3650 cps
out of all 96 ports simultaneously. All this speed is no surprise,
given the ASIC processor optimized for serial I/O. This is not a
general purpose processor (most other boards use the 80186), but an
I/O engine. This board is an excellent board for UUCP, because of
its extraordinary throughput.
The card has an extremely fast memory mapped i/o interface to the bus,
and can support 16MHz bus speeds. Any card that uses DMA or I/O
on the AT bus is automatically slow and inefficient, since DMA or I/O
cycles are much longer than 16 bit memory cycles on the AT bus. Also,
unlike any other boards, any number (1-8) of Equinox cards only uses
two 64K non-contiguous memory address ranges in total. This is in
contrast to many other cards, which use 64K of memory addresses per
16 port board! If you want to have 16 or more MB of memory in an
ISA 386, you have precious few memory addresses open on the the bus
(and they are all in the range from 640K-1024K). Typically, only 2 64K
address ranges are free below 1MB (ethernet cards are also using memory
mapped I/O these days and are addressed below 1024K). So if a system
has 16MB of memory, it can only have 32 ports (2 16 port boards). In
the same address space (2 64K ranges) you could have 8 equinox boards
(for a maximum of 192 ports per system).
There is no firmware (ROMs). Most other manufacturers put firmware
on the board, which makes it much more difficult to fix problems on
the board. There are no switches or jumpers to set. Up to 8 boards
in one system are supported (for a total of 192 ports) all on one
interrupt (of course it can be set for almost any interrupt). The
card or cards can run without interrupts (in a polled mode of
operation). Polling is much more efficient than interrupts if there
is a LOT of I/O. Also, there is an additional bus (a 10 pin ribbon
cable) between cards so that cards can communicate between each other.
Again, this is a board without switches and jumpers. Installation
requires nothing more than inserting the card, and running install.
The Equinox Megaport 24 port board supports the usual features such
as transparent print, automatic installation (no editing of files)
via "install". Note that currently custom(ADM) is not supported
(custom is a bad way to install drivers anyway). The software
installation is the cleanest and easiest we have seen yet.
As far as I/O loading, we thought we had seen it all with Computone
and Anvil both at 0.8 seconds CPU time per 100Kchars. The Equinox
Megaport is 0.1 seconds per 100Kchars. This is merely 8 times more
efficient than any other boards. (All results reported using the
SCO time(CP) command).
Since Equinox is a data switch company, there is a universe of
cabling options available. The board can directly terminate in
24 RJ-11 (6 wire) ports, or can terminate in 2 50 position Amphenol
PBX connectors so that you can use octopuses or harmonicas or data
racks or whatever connection options you want. They also have the
usual DB-25 termination option also. All these option greatly ease
the chore of wiring a system.
Driver availability: SCO XENIX 2.3 386 VPIX drivers now.
SCO UNIX and generic UNIX 3.2 (AT&T, Interactive, Enix) drivers
early to mid-july.
Of course, Equinox has been making data switches for 10 years, so
they have experience moving data. Also, Equinox is based in the
US (in Florida), not 5000 miles away. Since they have been in
business they have not had any financial problems (AAA rated on
D+B for their entire history) unlike Arnet and Computone which
both had severe financial problems. It is nice to have a stable
vendor for such an important part of the system.
-------------------------------< eof >----------------------------------
If you would like any additional information on these boards, you can reach
Continental at 1(203) 665-1355. They are located in Newington, CT.
echo $FLAMES >/dev/null
--
Gary Blumenstein, UNIX Systems Administrator // CIBA-GEIGY CORPORATION, USA
===========================================================================
Voice: (914) 347-4700 7 Skyline Drive, Hawthorne, NY 10502
FAX : (914) 347-5687 uucp: ...{philabs, gaboon}!crpmks!{sysadm, garyb}jonm@killer.DALLAS.TX.US (Jon Meinecke) (06/14/89)
This sounds like a really neat board. Perhaps someone more knowledgealbe in hardware details can explain why Mr Lukas writes: > ...DMA or I/O cycles are much longer than 16 bit memory cycles on the AT > bus... Is he referring to byte I/O, perhaps? Also, what does it mean to say that the card "can support 16MHz bus speeds"? I thought that AT-compatible bus speed is 8MHz... Has anyone actually installed one of these cards into a production system? If so, how many users, modems, printers, etc and what performance have you obsevered? Does it work with VP/ix and DOS Merge? How much does card cost? Jon Meinecke
brian@apt.UUCP (Brian Litzinger) (06/15/89)
From article <8367@killer.DALLAS.TX.US>, by jonm@killer.DALLAS.TX.US (Jon Meinecke): > This sounds like a really neat board. > > Perhaps someone more knowledgealbe in hardware details can explain why > > Mr Lukas writes: >> ...DMA or I/O cycles are much longer than 16 bit memory cycles on the AT >> bus... > In ATs DMA cycles operate at one fourth the clock rate. > > Also, what does it mean to say that the card "can support 16MHz bus speeds"? > I thought that AT-compatible bus speed is 8MHz... [Flame resistant suit ON...] I do not claim to be an expert on Megaport boards and I do not know if their product suffers from any of the following problems. I am simply providing the following information to answer Mr. Meinecke's general inquiry into these kinds of guestions. [Flame resistant suit OFF...] The IBM AT bus, if you can all it that, most people consider runs at 8Mhz. (It used to be 6Mhz on the original IBM AT). The 286 processor requires a clock of 2 times the processor speed. I.E. and 8 Mhz processor uses a 16 Mhz Master Clock. In the IBM AT the Master Clock drives the 286 Processor, and the Master Clock divided by 2 drives the bus. Therefore, the bus runs at 8Mhz. Many AT compatible and 386 AT machines use this same strategy. So imagine you want your system to go faster. You could simply replace the 16Mhz Master Clock, with a 20Mhz Clock. Your system might work if the electronics and memory can still operate at this higher rate. You might even design a system specifically to do this. However, your AT bus is now operating at 20Mhz/2, or 10Mhz, instead of 8. Many peripherals will be able to continue to operate correctly at this higher speed, but many will not. To their credit, some manufactureres use seperate clocks for the processor and the bus, thus avoiding this problem. On the otherhand, some people might not call an AT bus operating at greater than 8Mhz a problem, they might call it higher performance. In my experience, including working for Award Software, and Wyse Technology, I would avoid using greater than 8Mhz bus speed systems. It only leads to problems. Another performance point often mentioned is 16 bit transfers. By using the Memselect16 and LA address lines a peripheral can do 16 bit transfers. Unfortunately, using the LA address lines only allows you to decode memory in 128K chunks. To get finer precision you must use the SA address lines which occur approximately 50ns later than the LA address lines. This is not a problem for VGA/EGA cards because they can decode from 0xa0000 to 0xbffff, a 128K region. Some cards use various tricks to decode the SA address fast enough to do 16 bit transfers. However, all the schemes I have seen will not work in all computers. So would also recommend avoiding peripheral cards that try to decode smaller than 128K regions for 16 bit transfers. <> Brian Litzinger @ APT Technology Inc., San Jose, CA <> UUCP: {apple,sun,pyramid}!daver!apt!brian brian@apt.UUCP <> VOICE: 408 370 9077 FAX: 408 370 9291
garyb@gallium.UUCP (Gary Blumenstein) (06/19/89)
In article <8367@killer.DALLAS.TX.US> jonm@killer.Dallas.TX.US writes: > [ ...asking questions regarding the Equinox boards, (stuff deleted)] > [...] > Also, what does it mean to say that the card "can support 16MHz bus speeds"? > I thought that AT-compatible bus speed is 8MHz... Some buses on various 386 motherboards are tunable to run faster than 8Mhz. Mine runs at 10Mhz (I believe) and even has a separate "bus" crystal in addition to the CPU crystal. The problem arises when you use peripherals which have been designed to run on an 8Mhz AT bus. They can freak out and not work properly when used in a faster bus. This has happened to me. > Has anyone actually installed one of these cards into a production system? > If so, how many users, modems, printers, etc. and what performance have you > observed? Does it work with VP/ix and DOS Merge? How much does card cost? Mr. Lukas has told me that the Equinox board has been tested in the faster bus as well as with VP/ix, terminals, various applications and the like. He tends to give products such as this a gorilla test, then reports problems to the product development departments. He did this with Computone for years. I would have been willing to bet that he knew more about their products than their own Engineers. (no exaggeration here!) Without trying to sound like an Equinox salesmen, I have been told that anyone with questions regarding these boards is welcome to call him to get more info. (Tel # 1203-665-1355) * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Disclaimer: We use Continental as our vendor for SCO products and services however, the recent postings regarding the Equinox boards DO NOT, in any way, represent the policy or opinions of CIBA-GEIGY Corporation. - Gary -- Gary Blumenstein, UNIX Systems Administrator // CIBA-GEIGY CORPORATION, USA =========================================================================== Voice: (914) 347-4700 7 Skyline Drive, Hawthorne, NY 10502 FAX : (914) 347-5687 uucp: ...{philabs, gaboon}!crpmks!{sysadm, garyb}