Editing KIM-1 (section)

== History ==
MOS Technology's first processor, the [[MOS Technology 6501|6501]], could be plugged into existing motherboards that used the [[Motorola 6800]], allowing potential users (i.e. engineers and hobbyists) to get a development system up and running very easily using existing hardware. [[Motorola]] immediately sued, forcing MOS to pull the 6501 from the market.  Changing the pin layout produced the "lawsuit-friendly" [[MOS Technology 6502|6502]]. Otherwise identical to the 6501, it nevertheless had the disadvantage of having no machine in which new users could quickly start using the [[central processing unit|CPU]].

[[Chuck Peddle]], leader of the 650x group at MOS (and former member of Motorola's 6800 team), designed the KIM-1 in order to fill this need. The KIM-1 came to market in 1976. While the machine was originally intended to be used by engineers, it quickly found a large audience with  hobbyists. A complete system could be constructed for under {{nowrap|US$500}} with the purchase of the computer itself for only {{nowrap|US$245}}, and then adding a power supply, a secondhand [[Character-oriented terminal|terminal]] and a [[Kansas City standard|cassette tape drive]].

Many books were available demonstrating small [[assembly language]] programs for the KIM, including ''The First Book of KIM'' by  [[Jim Butterfield]] ''et al''.<ref name="Butterfield, KIM, First Book of" >{{cite book
  |last=Butterfield |first=Jim |author-link=Jim Butterfield
  |year=1977
  |url=https://archive.org/stream/The_First_Book_of_KIM#page/n0/mode/2up
  |title=The First Book of KIM
  |first2=Stan |last2=Ockers |first3=Eric |last3=Rehnke
  |isbn=0-8104-5119-0
  |publisher=Hayden Book
}}</ref> One demo program converted the KIM into a music box by toggling a software-controllable output bit connected to a small [[loudspeaker]].  Canadian programmer [[Peter R. Jennings]] produced what was probably the first game for microcomputers to be sold commercially, ''[[Microchess]],'' originally for the KIM-1.

As the system became more popular, one of the common additions was the [[Tiny BASIC|Tiny BASIC programming language]]. This required an easy memory expansion; "all of the decoding for the first 4 K is provided right on the KIM board. All you need to provide is 4&nbsp;K more of RAM chips and some buffers."<ref>{{cite magazine
  |last = Simpson
  |first = Richard
  |title = A Date with KIM
  |url = https://archive.org/stream/byte-magazine-1976-05/1976_05_BYTE_00-09_Shooting_Stars#page/n9/mode/2up
  |journal = BYTE
  |volume = 1
  |issue = 9
  |pages = 14
  |publisher = Byte Publications
  |date = May 1976
}}</ref> The hard part was loading the BASIC from [[cassette tape]]—a 15-minute, error-prone ordeal.

[[Rockwell International]]—who second-sourced the 6502, along with [[Synertek]]—released their own microcomputer in one board in 1978, the [[AIM-65]].  The AIM included a full [[ASCII]] keyboard, a 20-character [[fourteen-segment display|14-segment]] [[alphanumeric]] [[light-emitting diode|LED]] display, and a small [[cash register]]-like printer.  A [[debugger|debug]] [[machine code monitor|monitor]] was provided as standard [[firmware]] for the AIM, and users could also purchase optional [[read-only memory|ROM]] chips with an [[Assembly language#Assembler|assembler]] and a [[Microsoft BASIC]] [[interpreter (computing)|interpreter]] to choose from.

Finally, there was the Synertek [[SYM-1]] variant, which could be said to be a machine halfway between the KIM and the AIM; it had the KIM's small display, and a simple [[membrane keyboard]] of 29 keys (hex digits and control keys only), but provided AIM-standard expansion interfaces and true [[RS-232]] (voltage level as well as current loop mode supported).