From: Baltissen, GJPAA (Ruud) (ruud.baltissen_at_abp.nl)
Date: 2004-08-31 16:26:02
Hallo allemaal, I've got a question regarding compatibility: - The CBM drives keep a copy of the BAM in memory. CBM-HD doesn't; it loads the according BAM sector, changes the bit and saves the sector again. More reliable IMHO. OK, more I/O but a very acceptable price. If someone comes with a good reason to change this, I'll do it. But then one question: at what point is the BAM in memory written back to disk? I also wrote a PRG that copies a 8250 disk from one device to another. Mainly writen in BASIC, the actual transfer is done in ML. Speed: about 650 bytes/sec, a 8250 floppy is copied in about 25 minutes. Interesting fact: the built-in BACKUP command needs about the same time for a back-up. I wonder why. At this moment I copy the disk sector by sector. I started with reading a complete track into memory but had to reduce the number of reads because of an error. After finding the bug and a successfull run I did a run with a track at the time again. And this run took more time !!! It puzzled me and then I found out: the transfer of the the data from the CBM to my PC was very fast but took enough time to make the 8250 stop the diskmotor. In order to read the next track it has to start it again and this takes some extra time. Why is the above interesting? CBM-HD saves a 8250 disk as a D82 file and now I have a tool to save the original WordCraft disks. Which is interesting for Marko again :) -- ___ / __|__ / / |_/ Groetjes, Ruud \ \__|_\ \___| URL: Ruud.C64.org =====DISCLAIMER================================================================= De informatie in dit e-mailbericht is vertrouwelijk en uitsluitend bestemd voor de geadresseerde. Wanneer u dit bericht per abuis ontvangt, verzoeken wij u contact op te nemen met de afzender per kerende e-mail. Verder verzoeken wij u in dat geval dit e-mailbericht te vernietigen en de inhoud ervan aan niemand openbaar te maken. Wij aanvaarden geen aansprakelijkheid voor onjuiste, onvolledige dan wel ontijdige overbrenging van de inhoud van een verzonden e-mailbericht, noch voor daarbij overgebrachte virussen. The information contained in this e-mail is confidential and may be privileged. It may be read, copied and used only by the intended recipient. If you have received it in error, please contact the sender immediately by return e-mail; please delete in this case the e-mail and do not disclose its contents to any person. We don't accept liability for any errors, omissions, delays of receipt or viruses in the contents of this message which arise as a result of e-mail transmission. Message was sent through the cbm-hackers mailing list
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