emigh@ecsvax.UUCP (Ted Emigh) (08/15/86)
I have sent to net.sources the source for two Turbo Pascal programs to
check the CRC's of all files on a disk. I mentioned some time ago that
PC-SAS trashed my disk, and it was only by chance that I discovered this
before I made a periodic backup of my disk. This program will make a list
of all the files on the disk along with their CRC's. The next time it is
run, it will compare the newly generated CRC's with the old CRC's to see
if any files have been modified. I now use this program before any
backups that I do (and will continue to do so until I can be assured that
PC-SAS has been corrected).
Since several people have asked, let me describe my configuration and
how PC-SAS trashed the disk:
I have a PC-AT with 512K RAM. The resident program I have are FILEFAC
(from IBM, similar to the public domain SEARCH) and TIMEPARK (parks my
heads -- well actually the computer's heads after 5 minutes of nonuse).
This leaves 460K RAM free, which is close to the minimum of 450K that
SAS says is needed. The program that trashed the disk was print.sas on
the distribution disks. It needs more memory to run, but gives no warning
--just hangs up and writes bits of data to random parts of the disk. I
have had SAS run out of memory several times -- sometimes it puts a
message in the LOG, other times it has run amuck in the machine, corrupting
various parts of the RAM image of the operating system. SAS was very
good about contacting me about the problem, but were unable to detect
any problem (they didn't have a program such as I have sent to net.sources,
so how could they tell unless, by chance, it hit something important).
My recommendation to the people I distribute the package to is to either
not use it until it becomes "safe" or to use it off a Bernoulli box and
use FILECRC to make sure it doesn't selfdestruct.
I'll be in Chicago for the Joint Statistical Meetings if you want to
discuss it further.
--Ted--
--
Ted H. Emigh Genetics and Statistics, North Carolina State U, Raleigh NC
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