Databases, Systems & Networks

Around the time of the HP-67, an article in the Hewlett-Packard Journal, stated that electronic technology was no longer the only limitation of pocket calculator progress. The human interface was becoming an even greater barrier to adding more functionality. The HP-67 was an excellent example of the problem. It had three shift keys and most of its other keys had four functions. HP was running out of keyboard space for new functions, and many users found it difficult write and use numeric-only programs.

The HP-41C overcame these limitations by adding alphanumeric capabilities to both the display and keyboard. The keyboard had an « Alpha » key that toggled the keyboard between alpha and the normal calculator mode. (The alpha characters were printed on the slanted faces of the keys.) If the user needed a function not printed on a key, the name of the function could be typed in and executed. (About half of the HP-41Cs functions were preassigned to keys.)

Because typing out the name of a function could be cumbersome, the HP-41C added another toggle key called « user ». The user could assign any built-in function or user program to any key. Once the keyboard was placed in user mode, any assignments made by the user overrode the label on the key. (With the gold shift key, this allowed two user functions per key.) The user toggle state remained set even when the calculator was turned off allowing true keyboard customization.

To make it easy to remember keyboard assignments, HP provided keyboard overlays along with preprinted labels for all built-in functions and blank labels for user functions. In addition, whenever a key was held down, its function name was displayed. If it was the wrong key, the user could continue to hold it until the display showed « NULL » when meant the function was canceled.

Of course, HP didn’t just improve the human interface. The HP-41C had more memory (now non-volatile) than its predecessor, more functions, improved programming, and could be expanded with both RAM and ROM modules.

From The Introduction:

« The HP-41C represents a totally new concept in the design of Hewlett-Packard calculators. In fact, because of the advanced capabilities of the HP-41C, it can even be called a personal computing system. The HP-41C is the first Hewlett-Packard handheld calculator offering an exciting array of alphanumeric capabilities.With so many different kinds of calculator uses and applications in the world, we at Hewlett-Packard decided we could provide a significant contribution by designing and building you aquality calculator with expandable and flexible capability. The alphanumeric HP-41C is just the calculator. »

Alphanumeric Implementation

The HP-41C used a low power LCD display with 7 more segments than previous calculators. This allowed a full range of alphabetic characters. The characters were not as fully formed as a dot matrix display, but they had better contrast.

There was a special register on the HP-41C called the Alpha Register. It allowed up to 24 characters. This register was separate from the stack and the other storage registers. Alpha strings could be stored in normal registers or the stack but they were truncated to 6 characters when this was done. A function that shifted strings by 6 characters was included to make it easy to store long strings in multiple registers.

Expansibility

The HP-41C came with 63 « registers » of memory. Memory could be dynamically reassigned between storage registers and program memory. (63 registers was equal to 200-400 fully merged lines of program memory.)

Four ports at the top end of the machine allowed the user to plug in 4 more RAM modules which would increase the maximum register space to 319 or allow 1000-2000 lines of program space. (Or any compromise between those.) Later, the entire register space could be provided via a single « Quad Memory » module and Extended Memory was added to allow even more space..

The Optional Card Reader/Writer (82104A)

Because the HP-41C had continuous memory and because its application pacs came on ROM modules, a card reader was omitted. However, one could be plugged into the top end. (In less time then it takes to read this sentence.) The HP-41C was obviously not code compatible HP-67, however, a sophisticated translator was built into the card reader which translated programs to HP-41C code on the fly.

Lire la suite…

Caution

Many of these instructions were intentionally left out because used incorrectly they can confuse the calculator and cause either a lockup or a « Memory Lost » state. (If you get into the former state, you may need to remove the batteries to reset the calculator.)

You should backup anything important before first engaging in Synthetic Programming.

How Synthetic Instructions Work

HP-41 instructions are one or more bytes long. The calculator will only allow certain sequences, but with the tool below, you’ll be able create new sequences by entering code that the calculator allows and then grabbing bytes out of this code to create different instructions. These new sequences allow access to additional characters, additional sounds, more alpha editing commands, easy control of the calculator through direct access to system registers, etc. They make it possible to do new things and to reduce the size and execution time of programs. The byte grabber described below will allow you to remove individual bytes from programs you create so the the bytes that remain are interpreted differently.

Creating a Byte Grabber

You can use the following steps to create a Byte Grabber. Make sure to follow the steps exactly. If it doesn’t work the first time, try again. Note that the first step is a master clear so save anything important to cards, tape, or disk now!

1. Remove any accessory modules.
2. Do a Master clear by holding down the backspace key while turning on the calculator. The Display will show MEMORY LOST.
3. Assign « + » to the LN key by pressing ASN ALPHA + ALPHA LN.
4. Assign « DEL » to the LOG key by pressing ASN ALPHA D E L ALPHA LOG.
5. Press PRGM to witch to program mode. The display should show 00 REG 45.
6. Start catalog 1 by pressing CATALOG 1 and press R/S immediately before the display blinks. If the display blinks, you waited too long. Repeat this step as many times as necessary to get the R/S pressed before the display blinks. (The display will show the .END. instruction both before and after the blink, but you must press R/S before the blink.)
7. Press the ALPHA key to go into Alpha mode.
8. Press the backspace key. The display should now show 4094 RCL 01.
9. Press ALPHA to leave Alpha mode.
10. Press GTO .005 and you should see 05 LBL 03.
11. Press USER (if necessary) to enter User mode.
12. Press LOG 003 which uses the assignment you made earlier to DEL 3 steps. You should now see 04 STO 01.
13. Press ALPHA to go back into Alpha mode.
14. Press ? A A A A A A (Everything after the first A will probably display as « -« s.) Press exactly 6 A’s!
15. Press PRGM to leave program mode and ALPHA to leave Alpha mode.
16. Press GTO . . (press both dots)

The byte grabber should now be assigned to the LN key. Press AND HOLD the LN key which should display XROM 28,63. Keep holding the key until the calculator displays NULL because you don’t want to execute the byte grabber now. This would be a good time to save the calculator’s status on a card by pressing XEQ ALPHA W S T S ALPHA in case you accidentally destroy the byte grabber later.

Be careful in using the byte grabber. You may get a « MEMORY LOST » or lock the calculator if you use it incorrectly. If the latter happens, remove the batteries for a few seconds and return them. If that doesn’t work, try turning the calculator on a few times with the batteries out or leave them out for several hours. Lire la suite…

The PDP-12 was a 12 bit machine introduced in 1969. It sold for $27,900. The PDP-12 was designed as a successor to the LINC-8 and was compatible with LINC-8 software.

DEC.PDP-12.1963.102646098

Manuals at the end

Programmed Data Processor (PDP) was a series of minicomputers made and marketed by the Digital Equipment Corporationfrom 1957 to 1990. The name « PDP » intentionally avoided the use of the term « computer » because, at the time of the first PDPs, computers had a reputation of being large, complicated, and expensive machines, and the venture capitalists behind Digital (especially Georges Doriot) would not support Digital’s attempting to build a « computer »; the word « minicomputer » had not yet been coined.^{[citation needed]} So instead, Digital used their existing line of logic modules to build a Programmed Data Processor and aimed it at a market that could not afford the larger computers.

The various PDP machines can generally be grouped into families based on word length.

Members of the PDP series include:

PDP-1

The original PDP, an 18-bit machine used in early time-sharing operating system work, and prominent in MIT’s early hacker culture, which was to lead to the (Massachusetts) Route 128 hardware startup belt (DEC’s second home, Prime Computer, etc.). What is believed to be the first video game, Spacewar!, was developed for this machine, along with the first known word processing program for a general-purpose computer, « Expensive Typewriter ».

PDP-2

A number reserved for an unbuilt, undesigned 24-bit design.

PDP-3

First DEC-designed (for US « black budget » outfits) 36-bit machine, though DEC did not offer it as a product. The only PDP-3 was built by the CIA’s Scientific Engineering Institute (SEI) in Waltham, MA to process radar cross section data for the Lockheed A-12 reconnaissance aircraft in 1960.[1][2] Architecturally it was essentially a PDP-1 controlling[citation needed] a PDP-1 stretched to 36-bit word width.[3] Lire la suite…

source: Tim Mann

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** This list is historical information about computer-related products   **
** that Radio Shack sold in the 1980's.  It is NOT a list of items that  **
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** Radio Shack has probably discontinued most of these items, but check  **
** with them if you want to be sure.                                     **
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From a list created by Roy Hoff, Sr., with updates from Art McAninch,
Stan Slater, and Tim Mann.

Last modified on Fri Nov 26 21:29:17 PST 2004 by Tim Mann

Note on Tandy's numbering system:
Part numbers of the form xx0-xxxx and xx-xxxx are the same.
Part numbers of the form xxN-xxxx where N != 0 are (at least sometimes)
  non-US versions of xx0-xxxx, with N being a country code.

Lire la suite…