..@comment[from Eugene KUG Newsletter, Sept., Nov., & Dec. 1985 issues]

	     HINTS ON NSWEEP FROM THE HORSE'S MOUTH
			  by Doug Sears

I have written about Micro Cornucopia's SOG (Semi-Official
Gettogether) before in this publication.  During some strenuous
excavations in the dark corner of my computer room, I
rediscovered my SOG notes in a pile of ancient manuscripts, and
now I can tell you about one of the highlights of the SOG, Dave
Rand talking about his program NSWEEP.  Dave is working on the
Definicon 32-bit board for a living (see Micro C #25 and August
and September BYTE), but continues to improve NSWEEP in his spare
time.  You should all have v 2.07; there is a v 2.08 out, an
unauthorized update by an unknown person, which should be avoided
because it sometimes destroys files.  Dave is working on v 2.09,
using a smaller, faster SQueeze algorithm, and since that will
save about 4K of space, he may add some features, possibly a
bidirectional View or a left margin for the Print file command.

Dave had some useful comments on how to use NSWEEP.  I won't say
anything about whether features are "undocumented" or not,
because people (me included, of course) sometimes miss perfectly
well documented things.

1. To move a file to a different user number, just rename it, and
include the user number in the file spec.  For example,

B0:NSWEEP.COM  R  B14:NSWEEP.COM .

You can also do this with the wildcard rename.  I guess you can
throw MOVE.COM away now (I dumped SQ and USQ long ago, and use
NSWEEP instead).

2.  The little-known "Y" command.  To understand this command,
you need first to know about the mysterious "eighth bit," also
known as "bit 7" (counting from 0 to 7), the "high bit," or the
"parity bit."  Up to now, standard ASCII has been a seven-bit
code, leaving the eighth bit of a byte free for other uses (there
is a new eight-bit ASCII, but that's the subject of a different
article and irrelevant here).  In particular, the inner workings
of CP/M ignore the eighth bit of each letter you give it in a
file name, and then proceed to use some of those eighth bits for
marking special files.  

You will usually not see these high bits, even on '84 model
Kaypros which show letters with the high bit set as graphics
characters, because directory listing programs also ignore the
high bit.  If you do "STAT *.*" you'll be shown if there are any
Read-Only (R/O) or System (SYS) files.  A file which has the
eighth bit set on the first letter of its extension is a R/O
file.   The second letter marks a SYS file, and the third letter
marks a file for programs that make backup copies of all files
that have been changed (this is the Archive bit).  So there you
have the "RSA" you see when you try to use NSWEEP's Y command:  R
for read-only, S for system, A for Archive.

Y also lets you change the high bit of the first four characters
of the file name, called 1, 2, 3, and 4 in NSWEEP's terminology. 
High bits in characters 5, 6, 7, and 8 have very special meanings
in TurboDos, so they aren't used, in the name of compatibility. 
Here's a summary for that famous hypothetical file FILENAME.EXT.

FILENAME.EXT
------------
1234____.RSA

NSWEEP can display the marked characters in inverse video,
underlined, or whatever your screen can display, and NEWSWEEP.COM
included in ONKUG vol. 1 no. 9 is already set up for newer
Kaypros, the ones with graphics.  Unfortunately, '83-model
Kaypros show extra "0" characters instead of highlighting with
that setup.  To simulate highlighting on '83-model Kaypros, you
can make the lead-in and lead-out strings be appropriate
printable characters, such as "<" and ">".  This disturbs the
alignment of columns, but it's better than nothing. The lead-in
string is at location 104H (length of 0 to 6 at 104H, string
starts at 104H).  The lead-out string is at 10BH (same format:
length plus up to six characters).  I recommend SUPERZAP as the
easiest program to use for making simple patches like that.

Now that you know something about high bits, we can finally get
to NSWEEP's Y command.  The only trick you need to know is that
it only works on tagged files (just like the Q command).  So all
you do is tag the appropriate file, type "Y", and specify which
positions you want to change (any or all of 1, 2, 3, 4, R, S, or
A, separated by commas or not).  Any bits not specified will be
reset back to zero, so if you specify something other than 1-4 or
RSA, say some random letter like "k", then all bits will be
reset.  Some obvious applications come to mind.  Sometimes I get
Read-Only files from other people, and this saves me from having
to hunt up a disk with STAT on it.  Conversely, you can set your
precious files to R/O to keep yourself from accidentally erasing
them.  People with hard disks especially might want to look into
the programs that use the Archive bit for selective back-ups. 
You could use one of the other bits just to mark a group of
files.
for making simple patches like that.

Now that you know something about hi