>One other thing remains. Most PDP11s have what's called a 'line time
>clock' -- basically an interrupt every mains cycle. This is counted by
>the real time clock program in most OSes, and used to keep real time,
>etc. Of course if you move a machine from 60Hz to 50Hz power or vice
>versa, the real time clock will run slow/fast until you re-SYSGEN the OS
>for the appropriate frequency. This is not a big problem -- things still
>work -- though.
Actually, the KDJ11-B based machines allowed any of the following
settings for the LTC interrupt rate:
1) Line time clock (tied to power supply)
2) 50 Hz
3) 60 Hz
4) 800 Hz
Megan Gentry
Former RT-11 Developer
+--------------------------------+-------------------------------------+
| Megan Gentry, EMT/B, PP-ASEL | Internet (work): gentry!zk3.dec.com |
| Unix Support Engineering Group | (home): mbg!world.std.com |
| Compaq Computer Corporation | addresses need '@' in place of '!' |
| 110 Spitbrook Rd. ZK03-2/T43 | URL: http://world.std.com/~mbg/ |
| Nashua, NH 03062 | "pdp-11 programmer - some assembler |
| (603) 884 1055 | required." - mbg |
+--------------------------------+-------------------------------------+
I forgot to add that the sticker says it is set for 110v and 60hz.
We have 50hz. Perhaps it is necessary to change something on that score.
-----Original Message-----
From: Olminkhof <jolminkh(a)nsw.bigpond.net.au>
To: classiccmp(a)classiccmp.org <classiccmp(a)classiccmp.org>
Date: Saturday, 25 March 2000 21:54
Subject: BA23 Power Supply
>With all this talk of PDP11/23's I am looking at my BA23 with I think an
>11/73 CPU inside it.
>
>I haven't powered it up because it is set for 110v and we have 230v here.
>There's a switch on the back but a big sticker on the PS itself says to
>refer to the operating manual . . . sort of like there must be other things
>to do also.
>
>Does anyone here know about these things?
>
>Thanks,
>Hans
>
>
<I forgot to add that the sticker says it is set for 110v and 60hz.
<We have 50hz. Perhaps it is necessary to change something on that s<
That may impact the line time clock (time keeping) but not the PS as it's
a switcher.
Allison
<I haven't powered it up because it is set for 110v and we have 230v here.
<There's a switch on the back but a big sticker on the PS itself says to
<refer to the operating manual . . . sort of like there must be other thing
<to do also.
Well that switch has two positions... yours is in the wrong one for the
home town. The BA23s I've seen all had the "international" power supply.
The "see manual" reference is DEC prtoecting themselves. I presume it's
the standard Astec H7864A.
Allison
<restorable backup of the drive. The two floppies respond to DIR/Bad, and
<Init/Bad as devices DU1 and DU2:. But I get 'bad sector in system area'
<when I try to init. How do I low-level floppies?
Get a DEC Rainbow is teh common answer. There is no LLF utility with RT11
for RX50 (that dual drive).
Allison
The Bernoulli drives I have are all more or less the same, irrespective of
their generation. The PC interface card.cable uses a 37-pin (DC37) sub-D
connector and that's essentially a SCSI cable with the unused conductors
omitted. This makes for fewer conductors in the cable, but, if you look
inside the drive, the attachment to the controller is via a 50-conductor
ribbon cable, an adapter to which is attached to the bulkead at the rear of
the box. The interconnections between the drives are 50-conductor ribbon,
and, depending on the generation of the hardware, but for most of the 10 MB
8" drives, the controller is generally a separate card to which the drives
attached. It is more or less standard SCSI, though it doesn't work well
with other adapters or with ASPI drivers under DOS. I doubt the MAC uses
different internal hardware or cabling, though the BERNOULLI drives hung on
for a longer time in the MAC environment because of the MAC's smaller size
requirement. I have an old Xebec drive which uses precisely the same
cabling arrangement as the various BERNOULLI systems I have, and it also is
terminated at the drive/controller end in a 50-pin cable from its external
37-pin version. One of the BERNOULLI arrangements I have came with an
adapter to the more or less standard Amphenol (looks like a big Centronics)
50-conductor "Blue-Ribbon" connectors. This works because the controller
board on the Bernoulli's controller has soldered-in terminations.
I'd speculate that if you open a box and attach a typical SCSI-1
device-attachment cable not necesarily with both of the female connectors
attached, it will work with standard SCSI cabling. You'll have to make/buy
whatever the necesssary adapter from your MAC to the "SCSI-1" cable happens
to be, however.
Dick
-----Original Message-----
From: Bill Pechter <pechter(a)pechter.dyndns.org>
To: classiccmp(a)classiccmp.org <classiccmp(a)classiccmp.org>
Date: Tuesday, March 21, 2000 7:45 AM
Subject: Re: Mac to Bernoulli Cable
>> > I am looking for a cable to attach a Mac SE (DB25?) to an 8"
>> >Bernoulli Drive (Amphenol?) John Sowden
>>
>> Chances are I have it, but I don't know what it is. The SE SCSI port is
>> DB25F (so the cable is DB25M), explain the other connector in more
detail.
>> The three common ends are;
>>
>> DB25M, most older mac SCSI devices.
>> Centrontics50M, most SCSI devices.
>> HD (high density) C50M, compaq and some sony.
>>
>
>Anyone know anything about Centronics to DB50 pin typecables having
problems
>with termination or termpower on Suns...
>
>Was there multiple versions of the 50 pin pinout in the early days.
>
>Symptoms -- hung scsi bus on Sparcstations... inability to probe SCSI
>when used.
>
>Bill
>>With all this talk of PDP11/23's I am looking at my BA23 with I think an
>>11/73 CPU inside it.
>>I haven't powered it up because it is set for 110v and we have 230v here.
>>There's a switch on the back but a big sticker on the PS itself says to
>>refer to the operating manual . . . sort of like there must be other
>>things to do also.
>I would be very surprised if there was anything else to do but to toggle
>the power supply to 220 volt. The switch will also change for your 50hz
>cycle.
There isn't anything to change inside the power supply for 50Hz vs 60Hz.
All your software should be built or set to expect a 50 Hz line clock, too,
of course... (unless you like having your clock run at 5/6ths run
at actual speed!)
--
Tim Shoppa Email: shoppa(a)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
With all this talk of PDP11/23's I am looking at my BA23 with I think an
11/73 CPU inside it.
I haven't powered it up because it is set for 110v and we have 230v here.
There's a switch on the back but a big sticker on the PS itself says to
refer to the operating manual . . . sort of like there must be other things
to do also.
Does anyone here know about these things?
Thanks,
Hans
Does anybody know if IBM still prints up copies of their famous (infamous?)
corporate songbook? Furthermore, can anybody buy one. That is someting I
want to do: Buy a IBM Corporate Songbook, & go to a *Macintosh Expo*, & bust
out singing! (I know, I'm sadistic. Thank you. I've worked very hard to
become so!)
____________________________________________________________
David Vohs, Digital Archaeologist & Computer Historian.
Computer Collection:
"Triumph": Commodore 64C, 1802, 1541, FSD-1, GeoRAM 512, Okimate 20.
"Leela": Macintosh 128 (Plus upgrade), Nova SCSI HDD, Imagewriter II.
"Delorean": TI-99/4A.
"Monolith": Apple Macintosh Portable.
"Spectrum": Tandy Color Computer 3.
"Boombox": Sharp PC-7000.
____________________________________________________________
______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com
>Anyway, the machine works. I would like to format some floppies and get a
>restorable backup of the drive. The two floppies respond to DIR/Bad, and
>Init/Bad as devices DU1 and DU2:. But I get 'bad sector in system area'
>when I try to init. How do I low-level floppies?
Are your floppy drives RX33's or RX50's?
A RX50 is a two-drive-in-one unit, grey faceplate, two orange marks
showing you how to insert the bottom floppy in upside down. You can't
format a RX50 on your RQDX controller, you have to do it elsewhere. PUTR is
a common choice on a PC, get it at ftp.dbit.com.
A RX33 is a TEAC 5.25" HD disk drive. Put a 1.2Mbyte disk in, tell
it "FORMAT DU1:", and you'll have it formatted as a RX33. A RX33
can also read/write RX50's, but it can't format them on a DEC RQDX
controller.
Note that there are third-party Q-bus controllers that let you format RX50's,
and if you're running RT-11 5.7 you can use FORMAT/SINGLE on these
controllers to make RX50's.
--
Tim Shoppa Email: shoppa(a)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
