Installing FAS under ESIX rev C

Uwe Doering gemini at
Mon May 7 03:48:48 AEST 1990

conklin at frith.uucp (Terry Conklin) writes:

>OS: ESIX Sys V.3.2, rev C w/all the goodies
>MACHINE: Joe Clone '386-20, w/2 industry standard 
>         2 serial/1 paralllel/1 game (disconnected) cards
>PLAN: Get 4 indialing ports via basically standard 
>      COM1, COM2, COM3 and COM4 ports
>GRIEF: Lack of ints, naturally. 
>       Current layout is:
>       COM3 -> irq 4, COM4 -> irq3, COM1 & COM2 -> irq 5
>CAUSE OF GRIEF: the shared int

> [ some stuff deleted ]

>I dug through all the device driver stuff for 7 hours now, and
>am a little tired. FAS's installation has 0 support for 
>ESIX, coming with a makefile for Interactive and Microport.
>However, the Interactive files clearly map almost -exactly-
>to the ESIX Installable Drivers layout (ESIX's theoretically
>drastically improved user-level device driver install package.
>Hey, I'll vouch for it. I can type "installpkg" and duck as
>well as anyone.)

I couldn't support ESIX because I have no access to a system running
this flavor of UNIX. But I know of at least one person who successfully
installed FAS on ESIX. As you already noticed the installation stuff
is the same as for ISC, mainly because this setup was developed by AT&T
and therefor most vendors of AT&T derived UNIX ports didn't want to
invent the weel a second time.

>idbuild (That's Installble Driverland Build Kernel, for people
>without user-level driver muck) has an interesting feature
>though when you run it with the FAS stuff in place. It wanders
>into deep space. No errors. No messages. No crash. NoTHING.
>Even running 'w' from another user shows -csh. Swell.

I don't use the scripts in the Link Kit. On 386/ix there is a program
/etc/kconfig which does all the work for you. Maybe you have a similar
command in /etc. If this doesn't work, too, then you're out of luck because
something seems to be wrong with the whole Link Kit. A faulty driver
should at least produce some message at kernel link time.

>If anyone here has run FAS (or whatever it takes) to get 
>shared IRQ's for COM ports under ESIX's latest and greatest.
>Please send me a line and clue me in.

I'm not sure whether you are aware that shared interrupts for serial
devices require special serial boards. Due to IBM's poor design of the
PC I/O bus interrupts can't be shared at the bus level. You need to
combine the interrupt lines of the two or more serial ports with
some special logic on the serial card itself. This OR-ed signal is
then wired to exactly on IRQ line on the PC bus.

The card you have seems to require a different IRQ line for each port
as most of the low cost multi-port boards do. Under DOS this doesn't
matter so much because you don't need all ports at the same time. Therefor
ports can share an IRQ line, but only one port may actually use the IRQ at
the same time. Under UNIX all ports must be able to work at the same time.

In short, you need a multi-port board that supports shared (or common)
interrupts at the hardware level. The FAS driver can work with shared
interrupts, but only if you use the proper hardware. One board that
is supported by FAS is the AST 4-port card. There are several clones
in the market that are usually less expensive than AST's original.
Of course, due to it's high flexibility you can easily configure FAS
for other shared interrupt cards.

BTW, the latest release is FAS 2.06 PL0. If you have an older version
you should get the newer release for maximum performance and reliability.

Uwe Doering   |  Domain   : gemini at
Berlin        |---------------------------------------------------------------
West Germany  |  Bangpath : ...!uunet!pyramid!tub!tmpmbx!geminix!gemini

More information about the Comp.unix.i386 mailing list