..@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