LZW is a great compression/packaging utility written by Randy Medd when he was with Telamon. The LZW algorithm, originally protected by a Unisys patent which expired in 2003, is now in the public domain, so everyone may use it freely.
LZW provides a convenient method of packaging MPE files while retaining their file system characteristics. LZW compression is highly efficent, and can provide up to 90% reduction in storage requirements in some instances. Here is an example of how to use LZW to upload/unpack a file.
You may download a version of LZW here:
-
lzw.wrq, WRQ labels-format NMPRG
- lzw.std.raw, raw STORE-to-Disk file containing NMPRG file
- lzw.std.wrq, WRQ labels-format STORE-to-Disk file containing NMPRG file
-
lzw.raw, raw binary file of NMPRG (see notes below)
- lzwcm.raw, raw binary file of CM PROG (see notes below).
For WRQ Reflection users, we recommend using the WRQ labels-format NMPRG.
Notes on uploading the raw NMPRG version of LZW to MPE:
This assumes you’ve downloaded the raw MPE/iX or MPE V version of LZW to a local file called LZW.RAW (or LZWCM.RAW) on a PC or Mac. You may use one of the following two methods to upload the file to your HP 3000:
- FTP
Start an FTP session (perhaps: click on <START>, select <RUN>, and then enter "FTP", connect to your HP 3000 and logon). Use the following FTP put command:binary put LZW.RAW LZW.PUB;rec=128,1,f,binary;code=NMPRG
or, on MPE V:
binary put LZWCM.RAW LZW.PUB;rec=128,1,f,binary;code=PROG
- WRQ Reflection Terminal Emulator
Connect to your HP 3000 and logon. Then issue the following MPE command::file lzw.pub;rec=128,1,f,binary;code=NMPRGor, on MPE V:
:file lzw.pub;rec=128,1,f,binary;code=PROGUpload the LZW.RAW file with the following commands:
<ALT Y> (i.e., enter Reflection Command Line mode) s lzw.raw to *lzw.pub binary rec=256or, on MPE V:
<ALT Y> (i.e., enter Reflection Command Line mode) s lzwcm.raw to *lzw.pub binary rec=256NOTE! the "rec=256" is important! Without it, Reflection and/or PCLINK may not upload the file correctly!