14 Jun
2009
14 Jun
'09
2:22 p.m.
Dave McGuire <mcguire at neurotica.com> wrote:
On Jun 14, 2009, at 10:09 AM, Gordon JC Pearce wrote:
I couldn't have described the ports any better myself. :-)
The rubber case might just be one of the third party industrial cases
for the HP-41 for it to better survive hostile environments.
I don't think HP every did one, but I remember seeing other companies
making them. No names pops up in my head right now, though. This was a
long time ago. (Still have my 41CX around.)
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt at softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
> I spotted what looked like an odd
rubber-cased HP41 on a stall at a
> car
> boot sale. The guy also runs a small army surplus shop so although I
> didn't get it there I might ask him about it if I go in during the
> week.
>
> It had four openings at the back about the size of a matchbox end-on,
> with brown flexiprint circuit stuff folded over plastic tabs in the
> middle of each one.
This description matches the expansion slots on a standard HP-41.
What's with the rubber case, I wonder? Some sort of protective cover
like the ones available for most mobile phones? 
17 Jun
17 Jun
8:48 a.m.
On Sun, 2009-06-14 at 20:22 +0200, Johnny Billquist wrote:
The rubber case might just be one of the third party
industrial cases
for the HP-41 for it to better survive hostile environments.
I don't think HP every did one, but I remember seeing other companies
making them. No names pops up in my head right now, though. This was a
long time ago. (Still have my 41CX around.)
Annoyingly I realised I picked up an HP41C manual in a charity shop a
few months back, too. If I'd remembered that I had a manual for it at
home I'd have picked it up straight away...
Gordon
4:43 p.m.
Annoyingly I realised I picked up an HP41C manual in a
charity shop a
few months back, too. If I'd remembered that I had a manual for it at
home I'd have picked it up straight away...
The HP41 is one of the best docuemtned calculators _ever_ (the HP71B and
HP75C are similarly well-documented -- documetiation including not just
excellent user manuals and applicaiton manuals, but also schematics, bus
information and ROM sources..). And much of the documetation is available
on the web.
Darn it, there's even an active user group for HP calculators in the UK,
and yes, the HP41 is still discussed at meetings.
Lack of documentation is never a reason not to buy an HP41 :-)
BTW, the HP41C is 30 years old this year....
-tony
5:18 p.m.
On Jun 17, 2009, at 4:43 PM, Tony Duell wrote:
Yet another reason why my 41CX will never leave my desk. :-) I
have a big collection of HP calculators, but the 41 has always
impressed me more than any other model. I think it was because it
was advertised alongside all the 8-bitters of the early 1980s in the
magazines, as if it were a full-fledged computer...which, by all
definitions I'm aware of, it certainly is.
Annoyingly I
realised I picked up an HP41C manual in a charity shop a
few months back, too. If I'd remembered that I had a manual for
it at
home I'd have picked it up straight away...
The HP41 is one of the best docuemtned calculators _ever_ (the
HP71B and
HP75C are similarly well-documented -- documetiation including not
just
excellent user manuals and applicaiton manuals, but also
schematics, bus
information and ROM sources..). And much of the documetation is
available
on the web.
Darn it, there's even an active user group for HP calculators in
the UK,
and yes, the HP41 is still discussed at meetings.
Lack of documentation is never a reason not to buy an HP41 :-) BTW, the HP41C is 30 years old this year....
Very cool!
-Dave
--
Dave McGuire
Port Charlotte, FL
18 Jun
18 Jun
2:01 p.m.
Yet another reason why my 41CX will never leave my
desk. :-) I
have a big collection of HP calculators, but the 41 has always
I hae rather more desktop HP calculators than handhelds, but I still use
the latter a lot. I've got several 41's and many of the peripherals and
modules.
impressed me more than any other model. I think it
was because it
was advertised alongside all the 8-bitters of the early 1980s in the
magazines, as if it were a full-fledged computer...which, by all
definitions I'm aware of, it certainly is.
It is a computer, both in terms of the intenral architecture and the
facilities it provides to the user, IMHO. Or at least I can't think of a
sane defintion of 'computer' that would exclude it.
BTW, the HP41C is 30 years old this year....
Very cool!
4:03 p.m.
On Jun 18, 2009, at 2:01 PM, Tony Duell wrote:
You said "sane definition"...that's the key. Most of the unwashed
masses today will say "It's a calculator!" "Where's the
mouse?"
"Where's the 'start' button?"
-Dave
--
Dave McGuire
Port Charlotte, FL
impressed me
more than any other model. I think it was because it
was advertised alongside all the 8-bitters of the early 1980s in the
magazines, as if it were a full-fledged computer...which, by all
definitions I'm aware of, it certainly is.
It is a computer, both in terms of the intenral architecture and the
facilities it provides to the user, IMHO. Or at least I can't think
of a
sane defintion of 'computer' that would exclude it.
19 Jun
19 Jun
1:53 p.m.
It is a
computer, both in terms of the intenral architecture and the
facilities it provides to the user, IMHO. Or at least I can't think
of a
sane defintion of 'computer' that would exclude it.
You said "sane definition"...that's the key. Most of the unwashed
masses today will say "It's a calculator!" "Where's the
mouse?"
"Where's the 'start' button?"
-Dave
--
Dave McGuire
Port Charlotte, FL
4:12 p.m.
On Jun 19, 2009, at 1:53 PM, Tony Duell wrote:
This is classiccmp ;-). Most of the machines here don't have mide or
'start buttons' :-). If you're going to consider things like KIM1s
to be
'computers' it's very hard to exclude the HP41..
*None* of my computers have "start" buttons. ;)
It is a computer, both in terms of the intenral
architecture and the
facilities it provides to the user, IMHO. Or at least I can't think
of a
sane defintion of 'computer' that would exclude it.
You said "sane definition"...that's the key. Most of the unwashed
masses today will say "It's a calculator!" "Where's the
mouse?"
"Where's the 'start' button?" How many 'calculators' do you know of that can
be linked to a
couple of
3.5" disk drives, a pen plotter, an inkjet printer, an RS232
interface,
an HPIB interface, an 80 column video display and an ADC unit all
at the
same time. I've done that with an HP41.
They are glorious machines.
-Dave
--
Dave McGuire
Port Charlotte, FL
20 Jun
20 Jun
5:17 a.m.
>>>
*None* of my computers have
"start" buttons. ;)
<<<<
Hmmm, for the two mainframes* that I had close enough association with to
start them up
from scratch, the first** stage was to press the start
button on the MG set.
* ICL1905E, Honeywell Level 66/60
** Actually, I lie a little. The very first steps
(after turning on some 3KW of room lighting) were:
Check that the aircon was operational (and start it up if not)
Check that the processor swirches were set to "Halt" (It should have been
unless the previous
shutdown was a power failure or a use of the "Red Button")
NOW I could start the MG and wait for it to stabilse (a few seconds)
Then power on the processor and then peripherals.
(note that for todays equipment it is usually best to do it the other way
round)
Possibly have to load the firmware into the PF56 (the disk controller on the
1905E)
Ensure the right disk packs were loaded (they normally were, but ...) and
start them up (one start button each)
Start up the drum (another start button)
If booting from tape load the right tape (NO WPR!) on the right drive. (yet
another start button!)
Probably start up the comms processors (a Digico micro-16 for the 1905e; a
DN355 for the Honeywell)
Finally, I could press and release "boot" and let the processor "run"
....
If I was testing Exec mods on the 1905E I might have to recover from
mistakes in those mods.
[Luckily we never had one of those huge CDC fixed disks that had to run up
for HOURS after any power
interruption at all.]
OK, so these systems didn't have one "start" button - they had over a dozen
:-)
Andy
1:53 p.m.
*None* of my computers have "start"
buttons. ;)
At least one of mine does
No, I've nto started running Windows boxen. Rather, my Philips P850
has a frontpanel pushbutton labelled 'start'. It basically gets the
machine doing whatever you've sleected with the interlocked mode buttons
(read memory/register, write memory/register, start running a progrma,
single-step)
-tony
17 Jun
17 Jun
2:12 p.m.
[HP41]
I couldn't have described the ports any better
myself. :-)
I reckon I could :-)
12 connections --
3 power : Vbatt (battery +ve), Vcc (logic supply), ground
3 timing/sync : Phi_1, Phi_2 (2 phase clock), sync (bus cycle synchonisation)
ISA (Instruction and address -- 16 bit serial machine code address and 10
bit serial machine code instruction)
Data (56 bit serial data line)
2 slot selects (B3, B4, either floating or tied to a power line (I
forget which one) in the 4 possible combinations, so a module can tell which
slot it's plugged into)
PWO (Power off, turns off devices to save battery power)
FI (Serial flag input line)
A bus cycle is 56 clocks, corresponding to the 56 bits of a machine
register. Data (user program code, numbers, etc) is transfered serially
over the data line. Early on in a bus cycle, a 16 bit machine code
address is output on the ISA late, later on, a 10 bit instruction is read
back from the ROM [1] over the same line. Sync is asserted during those
10 clocks _unless it's fetching the second word of a 2 word instruction_ [2].
Note there's no read/write line, etc. The RAM chips have to decode the
instruction on the ISA line and start accepting data from the Data line
if it's a write instruction.
[1] Note that a machine code instruction can't be read from normal HP41
RAM, which can only output data onto the data line. If you want to do
machine code programming, you need some non-HP add-ons such as a special
RAM box that emulates a ROM
[2] this is actually a sensible idea. It means that a RAM chip, etc, only
decodes instructions when the sync line is asserted (to determine if it
should start reading or writing) and can't be fooled by the second word
of a 2-byte instruction (IIRC those are jumps, they never involve any
device other than the CPU).
Modules use the B3 and B4 lines to determine which port they are plugged
into. RAM modules (HP41C only, the maximum user RAM is built into CV and
CX machines) must be plugged in starting at port 1 unless you are doing
something _very_ strange. ROM modules are mapped to addresses 8xxx/9xxx
(port 1), Axxx/Bxxx (port 2), Cxxx/Dxxx (port 3) and Exxx/Fxxx (Port 4).
Most 4K ROM modules use the lower of the 2 pages assinged to a port, but
there's no reason why this has to be the case. Note that the card reader
ignores these lines, it can only really be plugged into port 4, and the
ROM always appears in page Exxx. Extended memory modules (-CX and others
with an extended functions ROM plugged in) use on of these lines so you
can have 2 such modules plugged in at the same time.
Can you tell I still use an HP41, I have been known to program it in
machine code :-)
-tony
5488
days inactive
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10 comments
5 participants
participants (5)
-
andyh＠andyh-rayleigh.freeserve.co.uk -
ard＠p850ug1.demon.co.uk -
bqt＠softjar.se -
gordonjcp＠gjcp.net -
mcguire＠neurotica.com