Maslin archive "virus"? (Was: Reasonable price for a complete SOL-20 system?

Fred Cisin cisin at xenosoft.com
Thu Oct 20 19:17:51 CDT 2016


> On Wed, 19 Oct 2016, Sam O'nella wrote:
>> Does that archive on classiccmp.org have the infected images removed or
>> cleaned? (Just curious as I remember this came up in a couple other forums
>> that I think one or two of the images did have a virus).
>
> an 8080/Z80 compatible CP/M virus???
> Or are you talking about a virus in some sort of MS-DOS image?
> Or an MS-DOS boot sector virus that wrote itself onto the "boot sector" of a 
> non-MS-DOS format?

OK, answering my own query, I did a trivial amount of GOOGLEing, and found 
discussion that said that "Stoned" was found in TD0 images of PC-7000 
MS-DOS 2.11.

That is an EXTREMELY common MS-DOS boot sector virus.  And was apparently 
in an image of an MS-DOS disk.  However, some "anti-virus" software would 
not find it, since it might ONLY look in the boot sector for that virus, 
not within an archive image.
Many other "anti-virus" software will get a lot of false positives, since 
it is only looking for a short "signature" - meaning that the staff in the 
anti-virus company extracts a short sequence from an infected disk, and 
then triggers whenever it encounters that particular sequence of bytes.

Are they skilled enough to extract a significant "signature" that would 
only occur in that virus, or do they grab a random sequence within the 
infected disk?


In any case, it is NOT likely to be a problem for any sort of Cromemco 
disk.  And the discussion that GOOGLE turned up was specifically referring 
to MS-DOS 2.11 of PC-7000.
Do NOT boot an 80x86 machine from one of those images.
BTW, ANY versions of MS-DOS 2.11 or 3.31 should be saved!  Even if it 
means manually "disinfecting".  Those were the most customized versions of 
MS-DOS, and included 3.5" disk formats that were not PC-DOS compatible, 
special versions of MODE.COM (for non-80x25 screens, and laptop 
externals), etc.


--
Grumpy Ol' Fred     		cisin at xenosoft.com


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