12 Nov
2015
12 Nov
'15
12:26 p.m.
On Nov 12, 2015, at 1:56 PM, Eric Smith <spacewar
at gmail.com> wrote:
...
Also DECtape does not have a specific directory format. It depends on
what computer line you are using (12-bit, 16-bit, 18-bit, or 36-bit),
and in some cases on which operating system you are running. Some
systems have software to access foreign DECtape logical formats; I
think the widest range of DECtape interchange software provided by DEC
was on TOPS-10.
Either that, or RT-11. Its FILEX program supports a bunch of different formats including
TOPS-10 format. (It used an odd way to read 36 bit data on a PDP-11 -- not using the read
all command, but using the read data command and grabbing the upper 2 bits from a CSR as
the words passed by. Tricky, you have to keep up with the DMA engine.)
paul