Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site sdccsu3.UUCP Path: utzoo!linus!vaxine!wjh12!genrad!decvax!ittvax!dcdwest!sdcsvax!sdccsu3!brian From: brian@sdccsu3.UUCP Newsgroups: net.micro.cpm Subject: Re: Intercepting BDOS errors Message-ID: <1952@sdccsu3.UUCP> Date: Wed, 20-Jun-84 09:29:31 EDT Article-I.D.: sdccsu3.1952 Posted: Wed Jun 20 09:29:31 1984 Date-Received: Fri, 22-Jun-84 01:04:21 EDT References: <1685@tekig1.UUCP> Organization: UCSD beer & pizza society Lines: 29 a Near the front of the BDOS there are 4 consecutive jump addresses. Normally, these have the addresses of BDOS's error handlers (which print the dreaded BDOS ERROR ON B sort of messages). You can replace them with addresses of your own if you wish. There is one each for disk read only file read only select error bad sector You will find them after the initial jump instruction in the bdos - for example, in a 56K cp/m, the bdos starts at CC06, and the jump addresses are at CC09, CC0B, CC0D, CC0F. In a BBS system I created once, these types of bdos errors should not ever have happened, so I replaced the addresses at boot time (dynamically) with the address of a subroutine that printed out "system error" and aborted the current operation, then jumped to location 0 to warmboot the system. Seemed to handle most of the problems. -- -Brian Kantor, UC San Diego ihnp4 \ Kantor@Nosc decvax \ akgua ----- sdcsvax ----- brian dcdwest/ ucbvax/