On 8/12/19 8:16 AM, Nigel Johnson via cctalk wrote:
> 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
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 8/12/19 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
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 8/12/2019 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 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 8/11/19 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.
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 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 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 8/11/2019 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.
_
From: cctech on behalf of Bill Gunshannon via
cctech
Sent: Sunday, August 11, 2019 9:59 AM
To: cct...@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
On 08/11/2019 10:40 AM, Nigel Johnson via cctalk wrote:
It's funny how licensing bodies do not recognise computer
engineers. I am a member if the IEEE, but since I first
wrote to the local body in 1974 they have never recognised
computer engineering as a discipline. After twenty years
of
/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
Jon Elson via cctalk wrote:
On 08/10/2019 01:29 PM, Dave Wade via cctalk wrote:
-Original Message-
From: cctech On Behalf Of Mark J. Blair
What term is used there for an engineer
who works in fields of general electronics?
An electronics engineer...
This war was settled in 1963
It's funny how licensing bodies do not recognise computer engineers. I
am a member if the IEEE, but since I first wrote to the local body in
1974 they have never recognised computer engineering as a discipline.
After twenty years of chip-level troubleshooting on DEC machines I spent
twenty
On 08/10/2019 01:29 PM, Dave Wade via cctalk wrote:
-Original Message-
From: cctech On Behalf Of Mark J. Blair
What term is used there for an engineer
who works in fields of general electronics?
An electronics engineer...
This war was settled in 1963 when the American Institute of
ech on behalf of Douglas Taylor via
cctech
Sent: Sunday, August 11, 2019 12:33 AM
To: Jon Elson; On-Topic Posts
Subject: Re: Pertec Interface Cable Length
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
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
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 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
> -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 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 8/10/19 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 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
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
> 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
On 8/9/19 10:05 PM, Douglas Taylor via cctech wrote:
I have a question about cable length - any electrical engineers in the
house?
I'm not one.
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
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