Path: utzoo!mnetor!uunet!husc6!bloom-beacon!randy
From: randy@athena.mit.edu (Randall W Winchester)
Newsgroups: comp.sys.cbm
Subject: Re: Random files problem w/sprites enabled on C64
Message-ID: <2364@bloom-beacon.MIT.EDU>
Date: 19 Jan 88 15:25:13 GMT
References: <1293@edison.GE.COM>
Sender: daemon@bloom-beacon.MIT.EDU
Reply-To: randy@athena.mit.edu (Randall W Winchester)
Organization: Massachusetts Institute of Technology
Lines: 49
Keywords: doing b-p:8,x with sprites enabled hangs up computer

In article <1293@edison.GE.COM> mfs@edison.GE.COM (Martin Sant) writes:
>Over the weekend I was pulling out my hair over a strange quirk I
>discovered while using random files on my C-64/FSD setup.  I found
>that the computer would 'hang-up' if I tried to use the 'b-p:'
>command while I had sprites enabled.  I tried to read and write data
>to the disk buffer and things would just quit after a random number
>of block pointer messages.  (I am using ua: and ub: for the sector
>read and writes)  I could regain control using RUN/STOP RESTORE.
>After I disabled the sprites, things worked fine.  Can someone out
>there in the net ether answer:
>
>1) Why does this happen ?
>
>2) Is it particular to the FSD or does the 1541 do this too ?

I had a program I was trying to debug for the longest time, and it
behaved the same way described here.  I tried it on both a C64 with
1541, and a C128 with a 1571.  I found that using sprites with random
files will result in random crashes.  There seems to be no rhyme or
reason to how long the program would run before hanging.  Using BASIC
AID, I found that it always stopped on a line that printed to the
file.

>3) Random files in general; I can use all of the sectors on the disk
>   can't I ?  I don't need to store any 'real' DOS files. Can I write
>   over the sectors where the directory, etc. are stored ?  Is there
>   a difference between the ua:/ub: and the u1:/u2: commands ?

No need to store any 'real' DOS files.  Just make sure you don't write
over the BAM (track 18, sector 0).  You might want to put a message on
the first directory sector, something to the effect that "this disk
contains random files."  Write the message as file names.  Then
when you list the directory, you'll have fair warning before writing
to the disk with the usual DOS commands.

>4) The JIFFY DOS stuff that was mentioned on the net several weeks 
>   ago:  Does it work ok with random files ?
>
>   Thanks in advance.
>-- 
>Mar Tan 
>GE Fanuc Automation 
>Charlottesville, VA 22901

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