The PDD2 implements a disk filing system for the Tandy Model 100, Tandy 102 and Tandy 200 portable computers. The nice thing is that booting is typing an one line Basic program and execute it. A program is loaded in high memory and a front end, FLOPPY, placed in the menu (current bank with the M200). By starting the front end the disk file system is started. Here it is getting really awkward; the options here are:
- F1 - Files
- Shows the files in the current disk bank (there are two disk banks on disk, see them as folders). This function should be useless, as the main screen contains no useful info.
- F2 - Load
- Transfers files from the current disk bank to the current computer memory bank. The contents of the current disk bank is shown. You just have to retype the name. Optionally you can choose a different destination name. Typing '1:' or '0:' switches disk banks.
- F3 - Save
- The reverse from Load.
- F4 - Bank
- Toggles between disk bank 0 and 1
- F5 - Kill
- Removes a file from the current bank. The filenames are shown, just retype the right one.
- F6 - Name
- Renames a file in the current bank. The filenames are shown, just retype the right one. And the new name.
- F7 - Format
- Formats the disk. Both banks of course.
- F8 - Menu
- Exits the disk file system and returns to the menu.
It is the contrast with the menu interface that makes the disk file system so inexplainable backwards and idiotic. The standard M100/102/200 menu is crude and simplistic by modern view, but for the time and limitations of that day, nice or even elegant. One might expect something similar for the disk file system program, which could be have dome in the same space. It isn't, and it might have something to do with why there are no Tandy computers nowadays :-).
There are two other programs on the utility disk provided with the PDD2. BACKUP.BA makes a backup of a disk. Alas this is done track by track, so you wind up changing disks 160 times for a full disk. FREMEM.BA is nice as it removes the disk filing system from memory.
The ROM based TS-DOS available from Club 100 solves this problem. Its interface is very similar to the standard M100/200 menu.
The picture show a D.I.Y version of the Mombo board, using a standard 27C256 EEPROM. Nice for testing without too much investment, not for every day use.