Another consideration with the TC02 is the small buffer. I don't know
what tape speed your drive runs at, but we lost a lot of sales to Dilog
because of buffer overflow on some of the faster CDC dirves. When we
came out with the TC03, it had a larger buffer to handle this.
cheers,
Nigel
On 8/12/19 8:11 AM, Douglas Taylor via cctech wrote:
> The bad news is that the cable lengths must be short to use the Qualstar
> 1260 with a PDP11, the good news is that I can lift and carry the tape
> drive! For many of us in this hobby that it is extremely important.
>
> After looking at
On 08/11/2019 08:00 PM, Douglas Taylor via cctech wrote:
This is where the electrical engineer could help. How do
you determine how long a cable the 74LS240 can drive?
Well, there are several considerations. First, it takes
some current to charge up the cable capacitance. More
current
On 8/12/2019 1:25 AM, Chuck Guzis via cctech wrote:
On 8/11/19 8:51 PM, Douglas Taylor via cctech wrote:
The TC02 is an Emulex TS11 emulation for pertec interface tape drives.
The J1 and J2 are sort of standard terminology, don't know why.
Ah, the *Emulex* TC02. You had me going there--DEC
On Sun, Aug 11, 2019 at 7:44 PM Chuck Guzis via cctech
wrote:
>
> On 8/11/19 6:00 PM, Douglas Taylor via cctech wrote:
>
> > I just looked at the TC02 and the Qualstar, there are termination
> > resistor packs on each. The Qualstar has a bunch of 74LS240 IC's near
> > the J1 and J2 pertec
On 8/11/19 8:51 PM, Douglas Taylor via cctech wrote:
>
> The TC02 is an Emulex TS11 emulation for pertec interface tape drives.
> The J1 and J2 are sort of standard terminology, don't know why.
Ah, the *Emulex* TC02. You had me going there--DEC also has a DECtape
controller called the TC02.
On 8/11/2019 10:44 PM, Chuck Guzis via cctech wrote:
On 8/11/19 6:00 PM, Douglas Taylor via cctech wrote:
I just looked at the TC02 and the Qualstar, there are termination
resistor packs on each. The Qualstar has a bunch of 74LS240 IC's near
the J1 and J2 pertec interface cables. The TC02
On 8/11/19 6:00 PM, Douglas Taylor via cctech wrote:
> I just looked at the TC02 and the Qualstar, there are termination
> resistor packs on each. The Qualstar has a bunch of 74LS240 IC's near
> the J1 and J2 pertec interface cables. The TC02 has a bunch of 74LS374
> chips near the J1 and J2
On 8/11/2019 7:01 PM, Jon Elson via cctech wrote:
On 08/11/2019 11:11 AM, W2HX via cctech wrote:
I seem to remember they were ribbon cables
with each odd/even pair twisted which probably meant one
active and one ground twisted together.
Or differential pairs.
No, both Pertec unformatted and
On 08/11/2019 11:11 AM, W2HX via cctech wrote:
I seem to remember they were ribbon cables
with each odd/even pair twisted which probably meant one
active and one ground twisted together.
Or differential pairs.
No, both Pertec unformatted and Pertec formatted interfaces
were TTL single-ended.
On 8/11/19 9:11 AM, W2HX via cctech wrote:
>> All of my Pertec tape drives (in the past) were located in
> a differentrack from the actual computer so the cables were
> always over 10' long and usually close to if not 20'. Never
> had a problem.
I stand by my commentary re Qualstar 1xxx drives.
_
From: cctech on behalf of Bill Gunshannon via
cctech
Sent: Sunday, August 11, 2019 9:59 AM
To: cctech@classiccmp.org
Subject: Re: Pertec Interface Cable Length
On 8/11/19 9:07 AM, W2HX via cctech wrote:
>> Would folding the
> excess cable up and covering with anti-static plastic hel
/even pair twisted which probably meant one
active and one ground twisted together.
>
> From: cctech on behalf of Douglas Taylor via
> cctech
> Sent: Sunday, August 11, 2019 12:33 AM
> To: Jon Elson; On-Topic Posts
> Subject: Re: Pertec In
On Sat, Aug 10, 2019 at 9:46 AM Douglas Taylor via cctech
wrote:
>
> I bought the long cables off ebay, so they have to be good? Right? I
> think the short cables came from a hamfest.
>
> The cables can be fairly long, I remember interfacing a TU80 to an
> Emulex QT14 (maybe) and the DEC cables
On 8/10/2019 1:56 PM, Jon Elson wrote:
On 08/09/2019 11:05 PM, Douglas Taylor via cctech wrote:
I have a question about cable length - any electrical engineers in
the house?
Connected a Qualstar 1260 tape drive to an Emulex TC02 qbus tape
controller in a pdp-11/53. The interface is pertec
> -Original Message-
> From: cctech On Behalf Of Mark J. Blair
via
> cctech
> Sent: 10 August 2019 18:03
> To: General Discussion: On-Topic Posts
> Subject: Re: Pertec Interface Cable Length
>
>
>
> > On Aug 10, 2019, at 1:57 AM, Dave Wade via ccte
On 08/09/2019 11:05 PM, Douglas Taylor via cctech wrote:
I have a question about cable length - any electrical
engineers in the house?
Connected a Qualstar 1260 tape drive to an Emulex TC02
qbus tape controller in a pdp-11/53. The interface is
pertec with 2 50 pin cables.
When I use a
On 8/10/19 9:45 AM, Douglas Taylor via cctech wrote:
> I bought the long cables off ebay, so they have to be good? Right? I
> think the short cables came from a hamfest.
>
> The cables can be fairly long, I remember interfacing a TU80 to an
> Emulex QT14 (maybe) and the DEC cables were round and
> On Aug 10, 2019, at 1:57 AM, Dave Wade via cctech
> wrote:
>
>>
>> I have a question about cable length - any electrical engineers in the house?
>
> Its electronics, rather than electrical engineering. Electrical Engineering
> is power distribution.
At least in the US, "Electrical
On 8/10/2019 4:57 AM, Dave Wade wrote:
-Original Message-
From: cctech On Behalf Of Douglas Taylor
via cctech
Sent: 10 August 2019 05:06
To: General Discussion: On-Topic Posts
Subject: Pertec Interface Cable Length
I have a question about cable length - any electrical engineers
> -Original Message-
> From: cctech On Behalf Of Douglas Taylor
> via cctech
> Sent: 10 August 2019 05:06
> To: General Discussion: On-Topic Posts
> Subject: Pertec Interface Cable Length
>
> I have a question about cable length - any electrical engi
> It doesn't work when I use a pair of 5 foot long flat ribbon cables.
> Are they too long? Do I need twisted pair type of cable? Is it
> possibly a termination problem?
These cables typically were twisted pair, at least inside cabinets.
(They might transition to round cables at bulkheads
On 8/9/19 9:05 PM, Douglas Taylor via cctech wrote:
> I have a question about cable length - any electrical engineers in the
> house?
>
> Connected a Qualstar 1260 tape drive to an Emulex TC02 qbus tape
> controller in a pdp-11/53. The interface is pertec with 2 50 pin cables.
>
> When I use a
I have a question about cable length - any electrical engineers in the
house?
Connected a Qualstar 1260 tape drive to an Emulex TC02 qbus tape
controller in a pdp-11/53. The interface is pertec with 2 50 pin cables.
When I use a pair of short flat ribbon cables, 18 and 30 inches each, it
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