[comp.sys.ibm.pc] skyplot planetarium simulator posted to binaries

GMS@PSUVM.BITNET (03/25/88)

I've posted a UUENCODed copy of my shareware SKYPLOT planetarium
simulator to COMP.BINARIES.IBM.PC.  If you want to use it you
should receive the 8 files, eliminate the header junk, concatenate them
(in the proper order), and UUDECODE them.  The result will be a binary
file in PKXARC format containing the program.  Now you must download the
file to your PC.  It is SELF-DEARCING!   just issue the name of the file as a
command and it will de-arc itself.

have fun and let me hear any comments.  Please feel free to distribute
it to others, post it on BBS's, etc...

gerry santoro
GMS @ PSUVM (bitnet)
. . . !PSUVAX1!PSUVM.BITNET!GMS  (uucp)
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-(*)-
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frotz@drivax.UUCP (Frotz) (03/30/88)

In article <37175GMS@PSUVM> GMS@PSUVM.BITNET writes:
>The result will be a binary file in PKXARC format containing the program.  
>Now you must download the file to your PC.  It is SELF-DEARCING!  ...
>have fun and let me hear any comments.

	People! People!  Let's be aware of the latest (and scariest)
viruses and what they do to people's minds.  This looks like a very
nice package and I want to risk it, but I will have to wait until I
find an isolated machine.  (Or run it under FlexOS/386 with the DOS
Application Environment in protected mode;-) Just remember: "Not
everyone can be protected like this."


Frotz
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jcmorris@mitre-bedford.ARPA (Joseph C. Morris) (03/31/88)

In article <3288@drivax.UUCP> frotz@drivax.UUCP (Frotz) writes:
>                                         [SKYPLOT] looks like a very
>nice package and I want to risk it, but I will have to wait until I
>find an isolated machine.

The SKY.EXE file was constructed by creating a normal PKXARC archive,
then prepending the PKSFX.PGM code which provides the self-unpacking 
function.  The easiest way to test this is to use an intellegent file-
compare utility like SUPERC to match the suspect file against a known 
good copy of PKSFX.PGM.  If the delta report says that the first mismatch
is at decimal 9758 (the current size of PKXFX.PGM), you should be safe.
I did this, and got the expected (and safe) report that it matched.

Of course, this assumes that you got PKSFX.PGM from a trusted source.

An alternative way would be to have a program which strips off the known
number of bytes in PKSFX.PGM (9758) from the suspect file and writes 
out the remainder to disk.  This remainder is a standard ARC file
which can be investigated with PKXARC -t etc.

Finally, I could have (but didn't) tried the thing safely by turning off
the expansion chassis which houses both of my hard disks and rebooting.
A less drastic measure which I used to use was to modify the drive
controller card to add a switch which disabled the on-board PROM.  The
card could still be accessed by using raw IN/OUT instructions, but none
of the BIOS interrupts would be recognized.  Modifying one of the
original IBM HD controller cards to do this was trivial, but the newer
cards aren't as easy.