NetNews Usenet Archive 1992 #30/NN_1992_30.iso/spool/comp/os/linux/20585

Text File | 1992-12-15 | 1.6 KB | 37 lines

Newsgroups: comp.os.linux
Path: sparky!uunet!mcsun!Germany.EU.net!rrz.uni-koeln.de!unidui!math.fu-berlin.de!news.th-darmstadt.de!adams
From: [e-mail] (Adams)
Subject: Re: Serial IRQ polling
Sender: [e-mail] (The News System)
Message-ID: <[e-mail]>
In-Reply-To: [e-mail]'s message of 14 Dec 1992 14: 48:42 GMT
Date: Wed, 16 Dec 1992 01:38:12 GMT
References: <[e-mail]>
Nntp-Posting-Host: pdv2.fmr.maschinenbau.th-darmstadt.de
Organization: TH-Darmstadt
Lines: 23

In article <[e-mail]> [e-mail] (James Carpenter) writes:

>   Does Linux poll serial ports (i.e. can I use COM2 and COM4 at the same time
>   if they are both on IRQ 3). I have looked at the serial code but it just
>   gets me dizzy. And I do not see any mention of polling (which is what I
>   always thought was the correct phrase). But is Linux suppose to do this?
>   And if so PLEASE tell me that there is a trick to enabling it because
>   nothing I've tried works.

There is no reasonable way to poll a device in a multi user or
realtime environment. Attaching to a timer
will lead to a desastrous performance loss, and hooking the
CPU will disable multitasking.

If there would be enough interest, it would be neither too hard nor
too expensive to throw an expansion card together, handling 2-4 serial
ports without any intervention of CPU..... Those by commercial vendors
cost up to 4000 DM, devices used sum up to 150 DM ....

(Remember: 16 bit wide ethernet cards, together with DOS setup software
cost about 260,-- DM)

best adams