[Info-vax] Anyone interested in another public access system

[P. Sture]

In article <gs2jq1$c44$3 at naig.caltech.edu>,
 glen herrmannsfeldt <gah at ugcs.caltech.edu> wrote:

> In the days of small memory, caching files in memory was
> not possible.  The RT-11 file system allocates contiguously.
> As I remember, the first file open is at the beginning of the largest
> free area.  When another file is open, it is either at the
> beginning of another large free area, or at the middle of the
> free area being used by the previously opened file.  

I can't remember whether it was a DIBOL specific thing, but on the RT-11 
systems I worked with when opening a sequential file for output, the 
allocation made was half of that free space, truncating at file close. 
Therefore if more than one sequential output file was opened at the same 
time, you _would_ get fragmentation. When an output file became full, 
the system would ask you for a continuation file specification, then 
continue.

There was a trick in DIBOL to override this, by specifying to the open 
statement the number of blocks to be allocated. IIRC this also worked 
for the continuation file dialogue. Printer spool files were best aimed 
at a disk with plenty of free space.

-- 
Paul Sture