Editing Datapoint 2200 (section)

== Technical description ==
{| class="infobox" style="font-size:88%;width:30em;"
|+ Datapoint 2200 version I registers
|-
| style="text-align:center;"| <sup>1</sup><sub>2</sub>
| style="text-align:center;"| <sup>1</sup><sub>1</sub>
| style="text-align:center;"| <sup>1</sup><sub>0</sub>
| style="text-align:center;"| <sup>0</sup><sub>9</sub>
| style="text-align:center;"| <sup>0</sup><sub>8</sub>
| style="text-align:center;"| <sup>0</sup><sub>7</sub>
| style="text-align:center;"| <sup>0</sup><sub>6</sub>
| style="text-align:center;"| <sup>0</sup><sub>5</sub>
| style="text-align:center;"| <sup>0</sup><sub>4</sub>
| style="text-align:center;"| <sup>0</sup><sub>3</sub>
| style="text-align:center;"| <sup>0</sup><sub>2</sub>
| style="text-align:center;"| <sup>0</sup><sub>1</sub>
| style="text-align:center;"| <sup>0</sup><sub>0</sub>
| ''(bit position)''
|-
|colspan="15" | '''Main registers'''
|- style="background:silver;color:black"
| style="text-align:center; background:white" colspan="5"| 
| style="text-align:center;" colspan="8"| A
| style="width:auto; background:white; color:black;"| '''A'''ccumulator
|- style="background:silver;color:black"
| style="text-align:center; background:white" colspan="5"| 
| style="text-align:center;" colspan="8"| B
| style="background:white; color:black;"| '''B''' register
|- style="background:silver;color:black"
| style="text-align:center; background:white" colspan="5"| 
| style="text-align:center;" colspan="8"| C
| style="background:white; color:black;"| '''C''' register
|- style="background:silver;color:black"
| style="text-align:center; background:white" colspan="5"| 
| style="text-align:center;" colspan="8"| D
| style="background:white; color:black;"| '''D''' register
|- style="background:silver;color:black"
| style="text-align:center; background:white" colspan="5"| 
| style="text-align:center;" colspan="8"| E
| style="background:white; color:black;"| '''E''' register
|- style="background:silver;color:black"
| style="text-align:center; background:white" colspan="5"| 
| style="text-align:center;" colspan="8"| H
| style="background:white; color:black;"| '''H''' register ''(indirect)''
|- style="background:silver;color:black"
| style="text-align:center; background:white" colspan="5"| 
| style="text-align:center;" colspan="8"| L
| style="background:white; color:black;"| '''L''' register ''(indirect)''
|-
|colspan="15" | '''Program counter'''
|- style="background:silver;color:black"
| style="text-align:center;" colspan="13"| P
| style="background:white; color:black;"| '''P'''rogram '''C'''ounter
|-
|colspan="15" | '''15-level push-down address stack'''
|- style="background:silver;color:black"
| style="text-align:center;" colspan="13"| AS
| style="background:white; color:black;"| Call level 1
|- style="background:silver;color:black"
| style="text-align:center;" colspan="13"| AS
| style="background:white; color:black;"| Call level 2
|- style="background:silver;color:black"
| style="text-align:center;" colspan="13"| AS
| style="background:white; color:black;"| Call level 3
|-
| style="text-align:center;" colspan="13"| ...
| style="background:white; color:black;"|
|- style="background:silver;color:black"
| style="text-align:center;" colspan="13"| AS
| style="background:white; color:black;"| Call level 13
|- style="background:silver;color:black"
| style="text-align:center;" colspan="13"| AS
| style="background:white; color:black;"| Call level 14
|- style="background:silver;color:black"
| style="text-align:center;" colspan="13"| AS
| style="background:white; color:black;"| Call level 15
|-
|colspan="15" | '''Flags'''
|- style="background:silver;color:black"
| style="text-align:center; background:white" colspan="9" | 
| style="text-align:center;"| [[Carry flag|C]]
| style="text-align:center;"| [[Parity flag|P]]
| style="text-align:center;"| [[Zero flag|Z]]
| style="text-align:center;"| [[Sign flag|S]]
| style="background:white; color:black" | Flags
|}
The Datapoint 2200 had a built-in full-travel [[computer keyboard|keyboard]], a built-in 12-line, 80-column [[green-screen display|green screen]] monitor, and two 47 character-per-inch [[cassette tape#data|cassette tape]] drives each with 130&nbsp;[[kilobyte|KB]] capacity. Its size, {{convert|9+5/8|x|18+1/2|x|19+5/8|in|cm|abbr=on}}, and shape&mdash;a box with protruding keyboard&mdash;approximated that of an [[IBM Selectric]] [[typewriter]].<ref name="2200ref" /> Initially, a [[Diablo Data Systems|Diablo]] 2.5 MB 2315-type removable cartridge [[hard disk drive]] was available, along with [[modem]]s, several types of [[serial interface]], [[parallel interface]], [[Printer (computing)|printers]] and a [[punched card]] reader. Later, an 8-inch [[floppy disk]] drive was also made available, along with other, larger [[hard disk]] drives. An industry-compatible 7/9-track (user selectable) magnetic tape drive was available by 1975. In late 1977, Datapoint introduced [[ARCNET]] local area networking. The original Type 1 2200 shipped with 2 [[kilobyte]]s (KiB) of serial shift register [[main memory]], expandable to 8 KiB. The Type 2 2200 used denser 1 [[kilobit|kbit]] [[random-access memory|RAM]] chips, giving it a default 4 KiB of memory, expandable to 16 KiB. Its starting price was around US$5,000 ({{Inflation|US|5000|1971|r=-3|fmt=eq}}), and a full 16 KiB Type 2 2200 had a list price of just over $14,000.

The 8-bit processor architecture that CTC designed for the Datapoint 2200 was implemented in four distinct ways, all with nearly identical instruction sets, but very different internal [[microarchitecture]]s: CTC's original design that communicated data serially, CTC's parallel design, the Texas Instruments TMC 1795, and the Intel 8008.<ref>{{cite journal |first=Ken |last=Shirriff |url=https://spectrum.ieee.org/the-surprising-story-of-the-first-microprocessors |title=The Surprising Story of the First Microprocessors |journal=[[IEEE Spectrum]] |date=August 30, 2016|volume=53 |issue=9 |pages=48–54 |doi=10.1109/MSPEC.2016.7551353 |s2cid=32003640 |url-access=subscription }}</ref>

The 2200 models were succeeded by the 5500, 1100, 6600, 3800/1800, 8800, etc.

The fact that most laptops and cloud computers today store numbers in [[little-endian]] format is carried forward from the original Datapoint 2200. Because the original Datapoint 2200 had a [[Serial computer|serial processor]], it needed to start with the lowest bit of the lowest byte in order to handle carries. Microprocessors descended from the Datapoint 2200 (the 8008, Z80, and the [[x86]] chips used in most laptops and cloud computers today) kept the little-endian format used by that original Datapoint 2200.<ref name="shirriff" /><ref>{{cite web |url=http://archive.computerhistory.org/resources/text/Oral_History/Intel_8008/Intel_8008_1.oral_history.2006.102657982.pdf |title=Oral History Panel on the Development and Promotion of the Intel 8008 Microprocessor|page=5 |date=September 21, 2006}}</ref>