27 Apr
2013
27 Apr
'13
12:11 p.m.
On 27 April 2013 10:49, Paul Birkel <pbirkel at gmail.com> wrote:
All;
I'm curious as to what other manufacturers/systems supported the use of
block-oriented magnetic tape media along the lines of the DECtape (TU56)
and DECassette (TU60) drives.
Well, there is LINCtape, which DECtape is a modified derivative of
(and which DEC even made drives of, see the DEC made LINCs, LINC-8 and
PDP-12). There's also DECtape II (TU58), which is the thing that
everyone and their mother has an emulator for (it's the one that plugs
into a serial port, and holds 256KB on a tape).
Correct me if I'm wrong, but TU60 DECassette isn't a block format
media like the DECtape or DECtape II.
In particular, what about the use of standard
1/2" tape media under such
circumstances? A wear-n-tear problem given the multi-pass nature of this
use (especially if being used to store temp-files for the OS), but if that
scenario were avoided ...
That's why DECtape (the original) was rather thick and had much
redundancy of its tracks (two copies of all the tracks), same as
LINCtape did it; though I do believe that the LINCtape did have the
format different, LINCtape also ran "backwards" to DECtape.
I'd like to play around with some, but acquiring
either a DECtape or
DECassette unit looks to be somewhere between impossible and merely
seriously unaffordable -- not to mention obtaining media for use with
either. So I'm thinking about whether there are possibly other drives out
there for which I might construct a suitable controller to mediate between
the raw(er) mechanism and the OS.
TU58 DECtape II, all it needs is a serial port; it's compact, and the
protocol of the controllers is relatively well documented. You can
find all sorts of implementations of DECtape II; ranging from the real
thing, to the "we made a small bit of IC and flash look like a pair of
DECtape IIs", to "what hardware? My PC *IS* the drive."
Fun fact about the software emulation of the DECtape II, is that there
is no limit on the size (beyond the addressable range of the protocol
of course). Hilariously, you *CAN* boot RT-11 off of a DECtape II that
thinks it's the size of an RL02 pack... Being it's running off a
serial port, it's as fast as you would think it is. (At least no
rewind time like on the actual DECtape II!)
I'm rambling, so I'm going to apply the magical power of "shutting up"
now.
Cheers,
Christian Gauger-Cosgrove