Page:CTSS programmer's guide.djvu/39

 decrement, and the address of the first track of the file in the address and tag. The fourth word contains the number of tracks used by the file in the address, and the date the file was last used (day, month, and last digit of year, coded as MMDDY, in octal) in the decrement.

If the user exceeds his track quota while writing a file, there will be an automatic temporary extension of his quota. This will allow him to complete any file he has begun; it will also allow for the automatic dumping of his machine status in case of system shut-down (see "System Service Changes and Supervisor Messages"). As soon as the track quota is exhausted the supervisor will notify the user of the fact. The extension will be maintained when the user issues. When he next logs in, he should relieve the excess in his track quota by adequate deletions. Should he fail to do this, a sufficient number of his oldest files will automatically be dumped at the next disk editing to restore his track quota to normal; the procedure for dumping these files will be similar to that for over-age files (see "Disk Editing Procedures").

Keypunching and Card Input to the Disk
Normally, it is expected that casual program writing, editing and data generation will be done directly from the user's console. Even for the case of long programs which are too tedious for the programmer to type, a trained typist can still type the program directly into the disk memory. However, for various reasons such as distance, convenience, or exchange with other computer centers, it is still sometimes necessary to input punched cards. In this case, input cards must be brought, with an appropriate control card, to the Center Dispatching Area for entry into the disk during the disk editing period, which occurs at least once a day.

Delayed Output and Disk Editor Control Cards from the Console
Normally, a programmer will find it more convenient to maintain brief but frequent interactions with his program through his console, but there will be occasions when large-scale output is desired. This output may still be obtained via the Center 1401 computers in the form 25