Wanted: CMD Hard drive or Lt. Kernal w 128 Daughterboard

[RobertB]

BTW, if there was a market for it...

Do you mean a commercial market in which you would sell this item?

...I'd resurrect the ISAM database engine for the 128.

What is the ISAM database engine?

             Truly,
             Robert Bernardo
             Fresno Commodore User Group
             http://videocam.net.au/fcug
             July 24-25 Commodore Vegas Expo 2010 - http://www.portcommodore.com/commvex

[BigDumbDinosaur]

BTW, if there was a market for it...

Do you mean a commercial market in which you would sell this item?

No.  There is no such thing for the Lt. Kernal.  In fact, there's barely a commercial market for anything Commodore these days.

...I'd resurrect the ISAM database engine for the 128.

What is the ISAM database engine?

ISAM means Indexed Sequential Access Method, referring to one of several ways in which a database can be organized.  Due to the presence of the key file processor in the Lt. Kernal DOS, it is possible to set up a disk-resident database system that can be shared in a multiplexed environment, e.g., a multi-line BBS setup.

In ISAM, one or more fields in the records are designated key fields, and when a record is entered, modified or deleted, the database engine (a whole bunch of machine code) automatically inserts, removes or changes keys in the associated key file.  Information embedded near the head end of the data file (which actually contains the records) defines the key structures and how they are related to the record layout.  User-written programs that would access the database engine would not have to know anything about the internal implementation, only the organization of the record structure.  A record would be retrieved by passing the associated key into the engine, which would look up the key in the key file (the index) and using the record number paired with the key, retrieve the record from the data file.

ISAM was invented at IBM in the 1960s for use with CICS on System 360 mainframes, and is still in widespread use.  You can usually spot ISAM files on a system that uses them, as they exist in pairs, with one named .dat (the records themselves) and the other usually named .idx (the index).

My ISAM database engine came out of work I did in 1987-1988 to developed a truck leasing and billing system that ran on a MUXed Lt. Kernal system, with 11 C-128D user workstations and a C-64 acting as a print spooler.  During the early design stages, I discovered the aforementioned booby-trap with RELative files on a MUXed system.  Since concurrent access had to be implemented to make this system useful, I had to devise an alternate to the RELative file.  I ended up structuring a type 5 (contiguous data) file to look like a RELative file, but also included a record allocation map and a file and record locking mechanism to prevent clashes between workstations.  From there, I wrote the code to support ISAM-like operation.

I got the idea from the C-ISAM capabilities found on many UNIX systems of the time, just as Fiscal had gotten the idea for key files from the polyfile database engine that was part of the Point 4 minicomputer operating system.

[BigDumbDinosaur]

I have a option of what the sysgen is,  but would like to hear an explantion of what it does from other members,  thanks.

SYSGEN is an acronym for SYStem reGENeration, which is how the Lt. Kernal DOS is loaded on to the hard disk.  When Lt. Kernals were in production they shipped with the DOS loaded and ready for use.  However, it was possible through carelessness or other actions to damage the DOS, possibly rendering the system inoperable.  SYSGEN made it possible to reload the DOS and restore operation, which was done from a 5-1/4 inch floppy disk (the SYSGEN disk).  SYSGEN was also the means by which an upgraded DOS could be installed.

[RobertB]

In fact, there's barely a commercial market for anything Commodore these days.

Tell that to Jim Brain (various hardware) or Gideon Zweijtzer (1541U) or Jason Mackenzie (Psytronik Software) or Protovision (software/hardware).  Going farther afield, Matthew Leaman of AmigaKit (Amiga software/hardware and surprisingly, Commodore goods, too) has his business... the only business he has from which he makes a living.  I'm sure I'm leaving out other people.

My ISAM database engine came out of work I did in 1987-1988 to developed a truck leasing and billing system that ran on a MUXed Lt. Kernal system, with 11 C-128D user workstations and a C-64 acting as a print spooler.

Darn!  I can only dig out about 5 or 6 C128DCRs (not including that plastic European C128D).  A C64... no problem.  And of course, the Lt. Kernal is there (but only for the C64).

              Truly,
              Robert Bernardo
              Fresno Commodore User Group
              http://videocam.net.au/fcug
              July 24-25 Commodore Vegas Expo 2010 - http://www.portcommodore.com/commvex

[BigDumbDinosaur]

In fact, there's barely a commercial market for anything Commodore these days.

Tell that to Jim Brain (various hardware) or Gideon Zweijtzer (1541U) or Jason Mackenzie (Psytronik Software) or Protovision (software/hardware).  Going farther afield, Matthew Leaman of AmigaKit (Amiga software/hardware and surprisingly, Commodore goods, too) has his business... the only business he has from which he makes a living.  I'm sure I'm leaving out other people.

Compared to the halcyon days of the 1980s, there is barely a market.    We're not talking about millions of dollars worth of sales like there were 25 years ago.

My ISAM database engine came out of work I did in 1987-1988 to developed a truck leasing and billing system that ran on a MUXed Lt. Kernal system, with 11 C-128D user workstations and a C-64 acting as a print spooler.

Darn!  I can only dig out about 5 or 6 C128DCRs (not including that plastic European C128D).  A C64... no problem.  And of course, the Lt. Kernal is there (but only for the C64).

All that is needed to adapt the Lt. Kernal to the C-128(D) is an MMU daughterboard and a small modification to the 128's motherboard.  The DOS (assuming version 6.x or later) already has the 128 side covered.

BTW, are you interested in parting with any of those 128Ds?

[RobertB]

Compared to the halcyon days of the 1980s, there is barely a market. 

Yes, I know.  I still have issue 1 and 2 of Info magazine that listed dozens, if not hundreds of companies making goods for Commodore.

All that is needed to adapt the Lt. Kernal to the C-128(D) is an MMU daughterboard and a small modification to the 128's motherboard.

Yeah, I don't have the MMU (or at least, can't find it).

BTW, are you interested in parting with any of those 128Ds?

Not at the moment.

              Truly,
              Robert Bernardo
              Fresno Commodore User Group
              http://videocam.net.au/fcug
              July 24-25 Commodore Vegas Expo 2010 - http://www.portcommodore.com/commvex

[BigDumbDinosaur]

All that is needed to adapt the Lt. Kernal to the C-128(D) is an MMU daughterboard and a small modification to the 128's motherboard.

Yeah, I don't have the MMU (or at least, can't find it).

There is a source for the daughterboard if you're interested.

BTW, are you interested in parting with any of those 128Ds?

Not at the moment.

Aww.    I'm looking to get a functioning 128D system to do some software on.