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[Contents] [Part 6] [Part 8]


TECHNICAL FORUM

This month, there is a follow-up to last month's query by Dominik Behr about the Timex FDD3.

"I just got through reading Emulate issue 4 on-line and wanted to give a reply to one of the letters in the Technical Forum concerning the Timex FDD3 disk system. I'm no expert on the system, but I just wanted to answer in case no-one else did. (I can't believe that would happen!)" [It did - TEd]

"There is some info on the disk system at this site. It is a collection of some e-mails talking about (mostly) how to transfer files from the Timex disk system to a PC. The author used 22DISK to read the Timex disks on a PC and includes the setup configuration to read TOS disks. Mr Behr could try to contact the author (Wojtek) using the e-mail address in the file and ask him for a copy of TOS on disk. He should also be able to suggest a way of using 22DISK to copy TOS back onto a Timex disk."

"I also just came across an ad for CP/M 2.2 for the FDD3000 system (the one with the 64K bank built in) with Timex's original CP/M manual and Digital Research's official CP/M manual. This one's a rare bird as it was only released in Portugal after Timex Corp. folded. I don't know how widespread CP/M usage was on the Timex computers in Portugal."

Tech Ed's reply:

Thanks! Not only have I now found out about the Portuguese Timex computers, we also appear to have an answer to last month's query.

As for CP/M, my experience of this operating system has been gained on the Research Machines LINK 480Z and Amstrad CPC and PCW series. I know it could also be used on the Spectrum +3, but not on most versions of the Spectrum due to the memory layout. It would be interesting to know more about CP/M on the Timex.


TECHNICAL WRITES

Although nobody has sent me a message about this query, a friend, who occasionally reads this magazine, has asked for an explanation of "hand-blocking", a method sometimes used to transfer old games to different media.

Basically, it works like this:

  1. Use a tape header reader to determine the start line of the first BASIC block, and the addresses and lengths of other blocks.
  2. Reset the computer and MERGE the BASIC loader. After a pause, it should give OK. Programs larger than 7K may cause a system crash if they have been made MERGE proof. It should also be noted that all auto-run programs on Microdrives are MERGE proof.
  3. Edit the LOAD statements so that they access the new device rather than the tape, including filenames. If a screen is loaded by LOAD ""CODE, change this to LOAD *"m";1;"filename"SCREEN$ (or LOAD "a:filename"SCREEN$, or whatever your device needs). Any block which passes through any of the addresses 23672 to 23674 needs its start address added after CODE.
  4. SAVE the loader to the new medium. Remember the LINE parameter.
  5. Reset the computer. Except for screens and blocks which pass through 23672 to 23674, LOAD further blocks to their original addresses, and SAVE them to the new medium from those addresses with their original lengths. Remember to CLEAR one byte below the start address first, unless the bytes load to the system variables or printer buffer.
  6. Screens and frame-count-protect blocks (those which affect 23672 to 23674) need their contents preserved. CLEAR 32767 (25855 on a 16K) and LOAD the block to 32768 (25856 on 16K). SAVE it to the new medium from 32768 (or 25856) with its original length.
  7. When all blocks are completed, reset the computer and LOAD the loader from the new medium. The game should start normally.

Technical editor, Phil Reynolds, can be contacted by email, or faxed on (+44/0) 1543 428082.

Technical queries will generally be answered in the following issue of Emulate!.


[Contents] [Part 6] [Part 8]