Nascom News­let­ter

be connected, the second using the other port. The standard EPROMs are addressed at D000), though other addressee can be supplied. If you’re running at 4Meg a wait state has to be inserted.

To enter the Hobbit Monitor, as its called, type ED000 x y, where x is a 1 for T2, T4 or T-Bug, or 0 for Nas-Sys, and y is 1 for 2Meg and 0 for 4Meg clock speeds. So all monitors are supported. On execution HOBBIT tests the extent of RAM and takes the top 1.5k for its buffer and tape directory (or 3k for 2 drives). So if BAGIC is initialised ensure you answer its “SIZE” question and don’t just press Newline, or the directory and buffer will be overwritten.

As supplied the DCR monitor has 15 commands, the first, like disks, being FORMAT, called, as are all commands by the first letter of the command name, ie. in this case “F”. All new cassettes need formatting, and like disks, this will destroy any previously recorded data if you accidently format a used tape.

Each tape, when loaded into the DCR, has to be M)ounted. This transfers the directory to RAM. This is perhaps the most frustrating command as it takes so long – up to about 140 seconds. This delay is because the directory is stored in the middle of the cassette, and a cassette must be rewound (the E)nd command) before it is removed. So if you wish to use the other side of the cassette the tape has to be completely rewound (though it is done automatically) which takes about 95 seconds and then the directory half way through has to be read, a further 45 seconds.

Once Mounted the N)ame command lists to the screen the names of the files on that tape. The names are listed five at a tine down the screen, with an asterisk after each five to indicate more, and for you to press NewLine to print them. Finally the number of free “blocks” left on the tape is shown. Each tape can hold 50.5K or up to 69 blocks (or files, if each file is 1-block tong) per side it would be far better if the directory was listed across the screen in groups of, say, 4 filenames

Each file name can be up to 6 characters long, with no restrictions. This is a little short as you really need at least 6 characters for a name, with perhaps a further 4 for a description, eg. S/TREK.BAS or Hobbit.M/C

The K)ill command deletes all the files on one side of the cassette, whilst D)elete purges just one specified file. C)hange alters a file name. This is one Command I thought I’d never use, but it’s surprising how useful it’s become. S)elect and T)ransfer are used with a 2-drive set-up and are self explanatory. The X)it, ie EXIT, command returns to the standard Nascom monitor via MRET.