Subject: Distribution of RX50 images on sunsite

From: [email-masked] (Charles Lasner)
Date: 19 May 1994 15:29:18 GMT

In case no one's looked for awhile, the PDP-8/DECmate archive on sunsite 
is growing.  Several categories have been expanded while others have been 
fleshed out.

Of particular interest is the conclusion of archiving the back pages of 
pdp8-lovers, now available completely from inception in 1989 through the 
end of last month.  File organization is the same as the a.s.p archives, 
i.e., by month.  For example, last month's archive is 9404.lov, etc.

By popular demand, I am starting up an RX50 diskette image section in the 
directory ....../pdp-8/images/rx50.  Three different formats are 
contemplated:

1)	ENCODE format images that require OS/278 to be enhanced with the 
P?S/8 byte-mode RX50 non-system handler.  This will be implemented when 
the handler is completed.  Once done, this will allow DECmate users to 
manage RX50 diskettes without the help of PC's.  The current restriction 
of OS/278 itself causes the ENCODE program to be limited to handling 
images of the directory and data area of OS/278 diskettes only.  The 
slushware tracks cannot be copied, nor can any part of any other diskette 
where byte mode copy is required.  Using the P?S/8 byte-mode handler, any 
RX50 diskette can be ENCODEd completely, etc.

2)	WIMAGE format images that require a forthcoming modification to 
the PD program WIMAGE which is in turn distributed with FDFORMAT Version 
1.8.  The current version can only manage MS-DOS-worthy diskettes.  The 
enhanced version will support command line options to specify the 
physical format as RX50 regardless of content, etc.  Once updated, the 
WIMAGE program itself will be added to the archive.

3)	TELEDISK format images that are compatible with the last 
shareware version of TELEDISK (Version 2.12).  Note that there are some 
potential problems with TELEDISK although it generally works and is 
widely available.  It is highly recommended that any .TD0 file be 
validated with the TDCHECK program.

I need some feedback regarding the exact format of TELEDISK files.  These 
files come in two distinct flavors: a nearly uncompressed version and a 
highly compressed version.  The compressed version would seem to be the 
best to use for an archive, but there are problems:

1)	Some people have observed bugs in TELEDISK when creating 
compressed files.  TDCHECK confirms that the files are defective.  
Turning off the compression makes a longer but viable file.  The vendor 
of the program admits to the bug, but newer versions of the program 
aren't shareware and require a commercial license fee.  Moreover, the 
vendor hasn't even made a committment to fixing the bugs, i.e., there are 
commercial versions also known to have problems, etc.

2)	When using a compressed file, TELEDISK runs a lot slower.  It is 
faster, and perhaps produces a smaller archive file to use something like 
PKZIP to compress an uncompressed file.  In any case, using the 
uncompressed .TD0 file allows TELEDISK to run much faster.

It's not reasonable to archive uncompressed image files on sunsite, thus 
we have to either use the compressed format where possible, or specify an 
archive format such as PKZIP to wrap the files in, etc.  And in the case 
of PKZIP we also have to specify which version as some people may not be 
able to run the latest PKZIP (Version 2.04g a/o this writing).  (Note: 
TELEDISK files are earmarked for PC usage already!  Thus, a compelling 
case can be made for using PKZIP 2.04g anyway!)

Once these file format decisions are made, the files themselves will 
start appearing on sunsite.  All categories of systems will be covered, 
but please note that some software requires optional DECmate hardware.

So, please indicate your choice of file format.  I will start stuffing 
files probably within a week.

cjl