9-track tape interfaces

9-track tape interfaces

[David C. Jenner]

Tim Shoppa wrote:
> 
> A lot, so I snipped it out!
>

As long as this thread is red hot, how about these questions:

I have an M4 Data 9914 tape drive with Pertec and SCSI interfaces.
It will do 800, 1600, 6250.  I want to set up and run 2.11BSD on a
Q-Bus system.

1) I'd rather not spend a lot to get a SCSI interface.  I now have
   Emulex TC02 and Dilog DQ130 Q-Bus controllers.  Is there
   any way these controllers are going to enable 6250 BPI?

2) Is there another Q-Bus, Pertec controller that will do 6250?

3) If I had a Q-Bus SCSI controller, would it enable 6250?

4) (Already asked in thread) Supposing I get the hardware to work
   at 6250, will 2.11BSD handle it?

Thanks,
Dave

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From: Tim Shoppa <SHOPPA@trailing-edge.com>
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>1) I'd rather not spend a lot to get a SCSI interface.  I now have
>   Emulex TC02 and Dilog DQ130 Q-Bus controllers.  Is there
>   any way these controllers are going to enable 6250 BPI?

Sure - I use them at 6250 BPI all the time.  The controller
doesn't have to know what density the data is at - the formatter
takes care of that.  If you absoultely insist on the computer
being able to switch the drive between 1600 and 6250 BPI modes,
you won't be able to achieve this with a TC02 or DQ130 under 2.11BSD,
but this is purely a frill as you can always select the mode from
the drive's front panel.

One thing you do have to worry about is data rate.  Pertec
formatted interfaces on "fast" buffered modern drives may want to suck
or spew data at rates that are often too fast for a lowly TC02 or
DQ130's capability to push data over the Q-bus.  Most modern Pertec-
formatted drives will let you throttle the rate to something reasonable.
And some more modern Q-bus controllers - like the Dilog DQ152 - have
internal buffers for handling such cases without having to throttle
the drive itself.

>4) (Already asked in thread) Supposing I get the hardware to work
>   at 6250, will 2.11BSD handle it?

Absolutely.  I use a Fuji 2444 and a Storagetek 2925 with a TC02
and 2.11BSD all the time in 6250 BPI mode.  I had to throttle the
data rates on both, but that's not such a big deal.

On the other hand, my Storagetek 2920, which is pretty much a 2925
without the cache option, doesn't let me throttle the data rate
at 6250 mode because there is no effective buffer.  These don't
work with my TC02 on a Q-bus machine, but they do work with a TC13
on a Unibus 11/44 or with a DQ152 on a Q-bus -11.

Also keep in mind that some third-party controllers don't interact
well with the fast polling that the most recent Q-bus CPU's can
do.  For example, my TC02 won't work at all with
a loaned Mentec M100 (roughly comparable with a 11/93) that I have.  
I've never had this problem with 11/83's and slower CPU's.

-- 
 Tim Shoppa                        Email: shoppa at trailing-edge.com
 Trailing Edge Technology          WWW:   http://www.trailing-edge.com/
 7328 Bradley Blvd		   Voice: 301-767-5917
 Bethesda, MD, USA 20817           Fax:   301-767-5927

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From: "Steven M. Schultz" <sms@moe.2bsd.com>
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Subject: Re: 9-track tape interfaces
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Tim -

	Howdy.

> I'm pretty sure that 2.11BSD properly handles TU81 density select
> in its TMSCP driver.  (Steve, can you confirm this?  I know you've
> made some effort to get write caching to work with TU81's over the years!)

	Indeed it does.  However TMSCP only defines 800,1600 and 6250 so
	on the quad density drive I have the 3200 setting must be selected
	manually on the front panel of the tape drive.

	Also the 'enable cache' works fine and makes a dramatic difference
	on a TU81+ attached to an 11/44.  The 'cache enabled' setting is
	sticky across open/close cycles so that you set it once manually
	when the first reel is loaded.  This was done to avoid having to
	modify dump/restore/tar/etc

> In any event, remote density selection/reporting is largely a
> frill, as any drive/controller combination that I ever used let you
> explicitly select it with a physical button or a switch and displayed
> the current selection in some useful way on the drive.

	Quite so.  Eons ago the one Cipher drive supported 800/1600 operation
	but the controller (TM11 clone) did not - you just made sure to
	select the density on the front panel when loading the tape

	Steve

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     Associate Professor John Lions, who  was instrumental in UNIX's
     acceptance in Australia, and in its popularity (through his two
     books) world wide, died last Saturday morning, after long
     illness.

Peter C



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In article by Peter Chubb:
>      Associate Professor John Lions, who  was instrumental in UNIX's
>      acceptance in Australia, and in its popularity (through his two
>      books) world wide, died last Saturday morning, after long
>      illness.

Gee, that's very bad news.

Thanks for the email, Peter.

	Warren

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From: Michael Sokolov <msokolov@harrier.Uznet.NET>
Date: 8 Dec 1998   07:19:34 GMT
To: pups at minnie.cs.adfa.edu.au
Subject: Re: 9-track tape interfaces
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   Dear Tim,
   
   You write:
> Hmm - you said it has a 40-pin connector.
   
   Yes. A straight flat ribbon cable connects it to the bulkhead, which has
a female 37-lead D-sub connector on the outside.
   
> Any obvious buffers (or banks of buffers) near the external connector?
   
   I have just spent a couple of hours tracing the etches on this board,
and here is what I have found out. One side of the 40-pin connector is all
ground (well, that's pretty obvious). On other side we have the following.
4 pins are permanently connected to pull-up resistors, and one pin is
permanently connected to a pull-down resistor. The other 15 pins are
connected through jumpers so that the user can connect or disconnect them
on an individual basis. Some of these go to different outputs of a 74S241
(dual 4-bit 3-state buffer), some go to a 7437 (unfamiliar with this IC),
and some go to a missing IC.
   
   Both halves of the 74S241 are permanently enabled. All 8 outputs of this
half are connected to different pins on the connector. 7 of them are
connected in the obvious way, but one is also connected to a pull-up
resistor (purpose non-understood, since the 3-state buffer is always
enabled). The jumpers for all 8 are ON. Then there are 3 pins that go to
the 7437. Although 3 pins of the connector are used for this, 4 pins of the
7437 are used. Two of the connector pins go through simple jumpers, and
both are OFF. The third pin is connected to two different 7437 pins through
different jumpers. One of them is ON and the other is OFF. Finally, there
are 4 pins that connect to a missing IC. The jumpers for all 4 are OFF.
   
   Now, does this tell you anything? :-)
   
> What are the date codes on the chips?
   
   The most recent dates are mid-1988.
   
> [Explanation of the mess with host-side density control]
   
   OK, from now on I'll only use the front panel switch for density
selection. :-)
   
> other times they're used to put the drive into streaming
> vs non-streaming mode, other times it's used to change the speed on
> a streaming drive.
   
   Hmm, this is another big gap in my knowledge. What does streaming vs.
non-streaming mean?
   
> The QT13 will support either IDEN-style density select or CDC-style
> density select [...]
   
   How does it determine which one to use? Is there a switch on the board?
   
> Yep, the RC25 also used the LESI bus.  (LESI="Low End Storage
> Interconnect".)
   
   Hmm, so then KLESI can do disk MSCP as well as TMSCP, right? Can it do
both simultaneously or only one at a time?
   
> They all look similar, and have similar mechanics, but the 81's
> electronics can do 6250 BPI, something an 80's can't.
   
   But they are all different CDC Keystones, right? This means that my
Keystone may or may not support 6250 BPI, right? How can I tell?
   
> No, the Keystone and the Kennedy 9300 are not the same beast.  The
> Keystone is a cute little streaming tape drive, while the 9300 is
> a humongous [...]
   
   "Cute little"?!?! I mean, I'm still amazed how I was able to get it
inside my apartment without knocking a couple walls down first! It's
certainly huge compared to the REALLY cute little Cipher we had at CWRU. (I
really miss that Cipher, BTW. Not only is it much smaller, according to
what I have been able to glean from the docs, it's much easier to load
tapes into than the Keystone. But then of course if this Keystone does 6250
BPI I will be much more than happy with it.)
   
   But hey, if the Keystone is a cute little baby, poor CSRG fellows! I
think Kennedy 9300 was their primary machine, and I can just imagine what
it is like if the Keystone is "cute little". Does the 9300 do 6250 BPI?
   
> [...] vacuum-column 125IPS machine.
   
   Yet another gap in my knowledge. I remember seeing the term "vacuum
columns" in the BSD documentation and having no idea what are they. Could
you enlighten me?
   
> (I'm sure someone will
> now chime in about the days when Univac UniServo drives ruled the
> earth...)
   
   Just out of curiosity, what are they?
   
   Sincerely,
   Michael Sokolov
   Cellular phone: 216-217-2579
   ARPA Internet SMTP mail: msokolov at harrier.Uznet.NET


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Subject: Re: 9-track tape interfaces
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On 8 Dec 1998, Michael Sokolov wrote:

> on an individual basis. Some of these go to different outputs of a 74S241
> (dual 4-bit 3-state buffer), some go to a 7437 (unfamiliar with this IC),

From my TTL Data Book: Quadruple 2-input positive-NAND buffer (Y=AB bar).
Outputs are 3, 6, 8, 11.  Corresponding inputs are 1/2, 4/5, 9/10, 12/13.
Vcc is 14, GND is 7.

>    Hmm, this is another big gap in my knowledge. What does streaming vs.
> non-streaming mean?

Streaming means that data can be supplied to the tape (or read from) fast
enough to keep it moving, as opposed stop/start (or more likely, stop
backspace start).  Requires double-buffering somewhere.

>    Yet another gap in my knowledge. I remember seeing the term "vacuum
> columns" in the BSD documentation and having no idea what are they. Could
> you enlighten me?

ROTFL :-)  Look at an old Sci-Fi movie some time, in particular the
obligatory IBM tape drives spinning back and forth.  The vacuum columns
were buffers; columns into which bits of the tape were sucked so as to
keep the tape moving past the heads at constant velocity (not sure how
good the clock recovery was in those days) whilst the reels did their
thing.  The column has various pairs of pressure sensors, between which
the tape was kept for that particular mode; if it crept past one hole,
it upset the pressure differential, and the pumps came into play...

Remember, folks; this real-time stuff was *before* micro-chips!  I still
remember looking at the old Cipher (I have the magic codes somewhere, that
allowed it to load with the door open etc) aghast that it had no vacuum
columns, but swing-arms instead...

> > (I'm sure someone will
> > now chime in about the days when Univac UniServo drives ruled the
> > earth...)
>    
>    Just out of curiosity, what are they?

Big BIG tape drives - real Sci-Fi material :-)

-- 
Dave Horsfall VK2KFU  dave at geac.com.au  Ph: +61 2 9978-7493 Fx: +61 2 9978-7422
Geac Computers P/L (FGH Division) 2/57 Christie St, St Leonards 2065, Australia


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Subject: Re: 9-track tape interfaces
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On Tuesday,  8 December 1998 at 19:49:40 +1100, Dave Horsfall wrote:
> On 8 Dec 1998, Michael Sokolov wrote:
>>> (I'm sure someone will now chime in about the days when Univac
>>> UniServo drives ruled the earth...)
>>
>>    Just out of curiosity, what are they?
>
> Big BIG tape drives - real Sci-Fi material :-)

UniServo was UNIVAC's name for all its tape drives, at least as long
as I was involved with them.  They were all vacuum column jobs, but
some were definitely ``cheap'' ones, such as the UniServo 6 and 12,
which were intended for smaller machines.  IIRC the latest ``big''
ones were the UniServo 16 and 20, at least when I was still involved
with UNIVAC.

Greg
--
See complete headers for address, home page and phone numbers
finger grog at lemis.com for PGP public key

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On Tue, 8 Dec 1998, Dave Horsfall wrote:

> Thanks for letting us know.  Damn...

Sic transit gloria mundi.

Damn.

John, why did you have to die?  You taught me everything that I knew.

Shit.

-- 
Dave Horsfall VK2KFU  dave at geac.com.au  Ph: +61 2 9978-7493 Fx: +61 2 9978-7422
Geac Computers P/L (FGH Division) 2/57 Christie St, St Leonards 2065, Australia


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From: Michael Sokolov <msokolov@harrier.Uznet.NET>
Date: 8 Dec 1998   14:13:08 GMT
To: pups at minnie.cs.adfa.edu.au
Subject: Re: 9-track tape interfaces
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   Dave Horsfall <dave at fgh.geac.com.au> wrote:
> From my TTL Data Book: Quadruple 2-input positive-NAND buffer (Y=AB bar).
> Outputs are 3, 6, 8, 11.  Corresponding inputs are 1/2, 4/5, 9/10, 12/13.
> Vcc is 14, GND is 7.
   
   Looks trivial, except that the author of the digital design textbook I'm
using has chosen to omit it. :-) Anyway, I have looked at the board again,
and all pins that go to the connector are outputs. This means that at least
in this form, with the U10 chip omitted, there are NO inputs on that
connector, only outputs.
   
   That missing chip could very well have to do with inputs, though. Hmm,
there are 4 lines going to that missing chip, and that sounds like the
number of input lines in some flavor of Centronics. On the output side, 8
pins go to the 74S241 and 3 pins go to the 7437, again suggesting 8-bit
output and some control signals.
   
   All this sounds very much like Centronics or some similar interface.
Figuring out what the host interface is and what do those myriads of
switches and jumpers mean would be harder, though.
   
   Sincerely,
   Michael Sokolov
   Cellular phone: 216-217-2579
   ARPA Internet SMTP mail: msokolov at harrier.Uznet.NET