1-bit architecture
| Computer architecture bit widths |
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A 1-bit computer architecture is an instruction set architecture for a processor that has datapath widths and data register widths of 1 bit (1/8 octet) wide.
An example of a 1-bit computer built from discrete logic SSI chips[1][2] were the Wang 700 (1968/1970)[3] and Wang 500 (1970/1971)[4] calculator as well as the Wang 1200 (1971/1972)[5] word processor series of Wang Laboratories.
An example of a 1-bit architecture that was actually marketed as a CPU is the Motorola MC14500B Industrial Control Unit (ICU),[6][7] introduced in 1977 and manufactured at least up into the mid 1990s.[7] One of the computers known to be based on this CPU was the WDR 1-bit computer.[8] A typical sequence of instructions from a program for a 1-bit architecture might be:
- load digital input 1 into a 1-bit register;
- OR the value in the 1-bit register with input 2, leaving the result in the register;
- write the value in the 1-bit register to output 1.
This architecture was considered superior for programs making decisions rather than performing arithmetic computations, for ladder logic as well as for serial data processing.[6]
There are also several design studies for 1-bit architectures in academia, and corresponding 1-bit logic can also be found in programming.
Other examples of 1-bit architectures are programmable logic controllers (PLCs), programmed in instruction list (IL).
Several early massively parallel computers used 1-bit architectures for the processors as well. Examples include the Goodyear MPP and the Connection Machine. By using a 1-bit architecture for the individual processors a very large array (e.g.: the Connection Machine had 65,536 processors) could be constructed with the chip technology available at the time. In this case the slow computation of a 1-bit processor was traded off against the large number of processors.
1-bit CPUs can meanwhile be considered obsolete, not many kinds have been produced and none are known to be available in the major computer component stores ((As of 2016), a few on eBay[9]). The Finnish company Partco still sells MC14500B as spare part in 2017.[10]
See also
References
- ↑ Wasserman, Katie (March 2006) [January 2004]. "LED calculators rule her house". Computer Collector Newsletter / Technology Rewind (Interview). Interviewed by Koblentz, Evan. Retrieved 2017-05-20.
Probably my most favorite is the Wang 500. It's got several unique things about it: a very unusual ROM memory made of hundreds of long enamel-coated wires wrapped around iron cores; a super-fast single-bit CPU built out of SSI logic chips; and of course tons of really cool-looking colorful keys.
- ↑ Product Service - Schematic manual. Wang Laboratories, Inc.. 1974. 03-0019-0. http://www.thebattles.net/oddments/wang/Wang_500_schematics.pdf. Retrieved 2017-05-20.
- ↑ "Programmierbare Rechner der 3. Generation mit einfacher IC-Technik" (in German). Kelkheim/Taunus, Germany: technikum29. Wang 700 & Wang 500. http://www.technikum29.de/de/rechnertechnik/ic-technik.
- ↑ "Wang Model 500 programmable calculator". Computer History Museum (CHM). http://www.computerhistory.org/collections/catalog/X222.83.
- ↑ "Wang 1200 - Wang WP History". 2010-03-07. http://www.wang1200.org/history.html.
- ↑ 6.0 6.1 Motorola MC14500B Industrial Control Unit Handbook - Theory and Operation of a CMOS one-bit processor compatible with B series CMOS devices. Motorola Semiconductor Products Inc.. 1977. 33-B78/8.0. http://tinymicros.com/mediawiki/images/e/ec/MC14500B_Handbook.pdf. Retrieved 2017-05-20. (NB. Also available in German language under the title "Motorola MC14500B Industrial Control Unit Handbuch - Theorie und Anwendung eines Ein-Bit-CMOS-Prozessors".)
- ↑ 7.0 7.1 Industrial Control Unit MC14500B. Semiconductor Technical Data (revision 3 ed.). Motorola. 1995. pp. 306–313. http://www.brouhaha.com/~eric/retrocomputing/motorola/mc14500b/mc14500brev3.pdf. Retrieved 2012-08-01.
- ↑ (in German) Fast alles über den WDR-1-Bit-Computer. Neuss, Germany: DATANorf. 1986. http://wdr-1-bit-computer.talentraspel.de/documents/wdr_1-40.pdf. Retrieved 2017-05-20.
- ↑ http://www.ebay.com/itm/Motorola-IC-MC14500B-MC14500BCL-100-NEW-/320837692605
- ↑ "CMOS-LOGIC IC 4500 DIP16". http://www.partco.biz/verkkokauppa/product_info.php?products_id=2532&language=en. "Also known as MC14500BCP"
Further reading
- "The Wang 700 ALU". 2012. http://6502.org:80/users/dieter/a5/a5_5.htm.
- "Wang 700 BCD correction". 2012. http://6502.org:80/users/dieter/bcd2/bcd2_3.htm.
- "The famous/infamous MC14500". 2005. http://www.6502.org/users/dieter/m14500/m14500.htm.
- "MC14500 and arithmetic". 2008. http://www.6502.org/users/dieter/a3/a3_5.htm.
- "A MC14500 modification". 2008. http://www.6502.org:80/users/dieter/a3/a3_6.htm.
External links
- "WDR-1-Bit Computer". OLD-COMPUTERS.COM. http://www.old-computers.com/museum/computer.asp?st=1&c=834.
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