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-
- Disk Imploder V2.27 by A.J.Brouwer. FreeWare
- ---------------------------------------------
-
-
- NAME
- DImp - Archives cylinders.
-
-
- SYNOPSIS
- DImp READ <SourceDrive> Ca[-Cb,Cc,..] <TargetFile> [-M?|-NB|-NC|-X] [+Readme]
- The collection of cylinders to be read must be specified by ranges, Ca-Cb,
- and/or single cylinders, separated by commas.
- -M? or MODE? = Compression mode, ? = 0-7, default = 5
- -NB or NOBITMAP = Ignore bitmap (normally unused blocks are cleared)
- -NC or NOCOMP = Do not compress cylinders
- -X or EXE = Create self-extracting overlayed executable
- +"Name of Readme file to be displayed during WRITE"
- DImp WRITE <DImpFile> <TargetDrive>
- DImp INFO <DImpFile>
- DImp ABOUT
- DImp will use ".dmp" or ".dex" filename extensions when trying to
- create or recognize DImp data files.
-
-
- DESCRIPTION
- DImp allows you to compress a subselection of cylinders from
- any floppy compatible device into a file. DImp is fast and
- sports a good compression ratio. Notably, DImp allows you to
- create a self extracting file with an appended readme text,
- thus providing you with a completely self-contained method of
- distributing a disk's contents in a file.
-
- There are four operation mode keywords; "READ" specifies
- that cylinders must be read, "WRITE" indicates that you wish to
- write cylinders encoded in a dimped file, "INFO" displays
- information about the contents of a file containing dimped
- cylinders, and "ABOUT" should be obvious.
-
- The cylinders are individually compressed, checksummed and
- stored, thus, in case of a transmission error, valid cylinders
- can be undimped, and the originator can then select, dimp and
- retransmit the faulty cylinders.
-
- The cylinders to be READ can be selected by entering cylinder
- numbers separated by commas, or a dash if you wish to specify
- a range of cylinders.
-
- When reading or writing, DImp can handle any device that
- supports the normal floppy 2 heads 11 sectors etc. layout,
- thus it is usable with f.e a RAD: or an FMS disk. You can omit
- the colon normally following these device names.
-
- Additional options include compression mode selection override.
- Given the fact that the tracks are compressed individually, the
- default mode 5 has a pretty optimal compression ratio, though
- the ratio isn't as good as it might have been if cylinder data
- had been treated as a continuous stream. This is a design choice
- intended to allow the aforementioned flexible handling of
- individual cylinders.
-
- If there's sufficient free memory, DImp will allocate buffers
- for a turbo compression algorithm. Also, reducing the crunch
- mode will speed things up, dramatically so if you don't have
- sufficient free memory for DImp to run in turbo mode. Lowering
- the crunch modes results in less efficient compression though.
-
- Next, there are a couple of option switches. NOBITMAP
- prevents DImp from discarding data that, according to the disk's
- bitmap, isn't used by the filing system. This option is rarely
- needed. If you suspect a disk to contain a program that uses a
- low level routine to read its information from that disk, this
- option might be required to prevent loss of relevant data.
- NOCOMP disables compression. EXE causes DImp to generate self
- extracting dimp files. These can be executed, and will write
- their contents to a disk selected by the user. Executable DImp
- files (.dex filename extension) can be treated as normal DImp
- files (.dmp filename extension) in that you can use DImp to
- WRITE these, or get INFO on them.
-
- Lastly, you may specify a filename containing text to be
- displayed during the writing or self-extraction of the dimp file
- you're creating. This allows you to include a fairly extensive
- comment on the contents of the disk. This readme filename must
- follow a "+" commandline indicator.
-
-
- EXAMPLES
- DImp READ rad 0-79 Work:Cylinders EXE +ram:blahblah
-
-
- TECHNOCRAP
- The self-extracting executable files generated by DImp are
- overlayed. This allows for the cylinder data to be spooled
- during the self-extraction process, resulting in much more
- modest memory requirements than the size of the executable
- would lead one to suspect.
-
- Thanks to resource tracking, transparent error management,
- modular algorithm linking, and sitting on the program for
- several years before releasing it, DImp should be very robust
- and return sensible error messages.
-
- DImp is pure and can be made resident.
-
-
- AUTHOR
- Albert-Jan Brouwer
- UUCP hp4nl.nluug.nl!cbmnlux!ecl001!ajbrouw
- UUCP cbmvax.commodore.com!cbmehq!cbmnlux!ecl001!ajbrouw
- FIDO: 2:281/614 (up for freq sometime fall '91)
-