27 Sep
2011
27 Sep
'11
2:40 p.m.
On 09/27/2011 07:17 AM, Chris Elmquist wrote:
On Tuesday (09/27/2011 at 06:00AM -0400), allison
wrote:
I use a pdp-11.
Warning it's slow! And it's only 512
sectors of 512bytes.
I'm likely to be writing a Linux app to
communicate with the TU58
very soon. I am restoring a TU58 and need a debug tool to talk to it
more conveniently than using one of my PDP-11. The unique option similar to this that I want is
one MS-DOS driver in
SpareTime Gizmos, but to use the TU58 as one MS-DOS storage unit. But, what
I have in mind is similar but different at the same time. I want to manage
the TU-58 contents in DEC native format.
The TU58 has no native format. It's addressed as 512byte blocks.
Any other format is imposed but the host system, for example RT11,
RSX11, VMS (VMboot and VMS). So, in the next couple weeks, I might have something
that can chat with the
drive and read/write some blocks.
But, it'll be for Linux. I don't get anywhere near any Microsoft OS.
Also, SPc noted,
The usual problem if the PS is not failed is the drive rollers have
turned to goo.
I have yet to see one that has not. A goo roller will foul a tape.
* In appeareance the Current flows by the main
board of the device (the RED
led indicates so)
On my unit, the red LED only makes a brief flicker as the unit
is being
powered up and down. Scope reveals life-- 8085 CPU is executing stuff.
I see the UART being polled, etc. so I have been believing mine is closer
to life than not.
Is the red LED supposed to come on and stay on? My
impression from the
tech manual is that the red LED is a fault indicator of some sort so
I was OK with it being mostly off. If it's supposed to be mostly on,
then I have more debug to do.
It stays on when the system in sync with the host or task complete.
It's not only a power indicator.
Ther is a manual for the Tu58 that gives the protocal (mostly).
I have replaced the capstan rollers in this thing and
am really just
beginning the debug/restoration. I'm probably also going to find that
the first tape I put in it is going to break when it starts moving...
of the dozen or so tapes I found with the unit, four of them already
had the drive belt broken inside the tape cartridge.
Could be a lot of effort to get 512, 512-byte blocks ;-) But hey,
it's fun.
From memory..
Not that hard, basically hit it with a break, wait for an ack packet,
respond with a read block N command packet and wait for data as four
checksummed packets and a status packet.
FYI when it is sending data the host MUST be able to accept and buffer
at least 128 or 512 bytes (MRSP allows for an wait on ack for each 128 bytes
[pdp11/44 overflow fix] where the RSP protocol assumes you can buffer the
whole mess at line rate.
The protocal is a bit convoluted.
Allison
Chris