Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!watmath!clyde!burl!ulysses!bellcore!petrus!scherzo!allegra!princeton!orsvax1!pyrnj!caip!lll-crg!lll-lcc!qantel!intelca!glen
From: glen@intelca.UUCP (Glen Shires)
Newsgroups: net.micro.pc
Subject: Re: Re: DOS re-entrancy
Message-ID: <230@intelca.UUCP>
Date: Fri, 7-Mar-86 14:52:39 EST
Article-I.D.: intelca.230
Posted: Fri Mar  7 14:52:39 1986
Date-Received: Sat, 8-Mar-86 23:58:45 EST
References: <103@nvuxr.UUCP> <137@suneast.uucp>
Organization: Intel, Santa Clara, Ca.
Lines: 23

> The obvious solution (so obvious it's gonna be posted umpteen times):
> grab the int21 vector yourself, and set an "indos" flag when a user call
> comes in. Your driver then checks "indos" on interrupt: if set, it
> sets "servicewanted" and lets DOS continue; otherwise it just performs
> the required activity (including int21's).. On the way out, DOS returns
   :
> Geoff Arnold, Sun Microsystems Inc. (East Coast Division)
> SnailMail: One Cranberry Hill, Lexington, MA 02173; 617-863-8870 x136 
> UUCP:      [East Coast] linus!security!sunne!suneast!geoff
>            [West Coast] {hplabs,ihnp4,nsc,pyramid,decwrl}!sun!suneast!geoff

Obvious yes, functional no! atleast not with a LOT of tweaking.

DOS isn't that clean because:

    - It recursively calls itself
    - It has some functions that don't ever return (like TERMINATE)
    - It has plenty of undocumented function calls.
    -- 
^ ^    Glen Shires, Intel, Santa Clara, Ca.
O O     Usenet: {ucbvax!amd,pur-ee,hplabs}!intelca!glen
 >      ARPA:   "amd!intelca!glen"@BERKELEY
\-/    --- almost relevant