Level I BASIC
| Designed by | Steve Leininger |
|---|---|
| First appeared | 1977 |
| Influenced by | |
| Tiny BASIC, Palo Alto Tiny BASIC | |
| Influenced | |
| TRS-80 Level II BASIC | |
Level I BASIC is a dialect of the BASIC programming language that shipped with the very first TRS-80, the TRS-80 Model I.
Background
The original prototype of the TRS-80 Model I ran Li-Chen Wang's public domain version of Tiny BASIC. During a demonstration to executives, Tandy Corporation's then President Charles Tandy tried to enter his salary, but - as Tiny BASIC used 2-byte signed integers ranging up to only 32,767 - wasn't able to. The result was a request for floating-point math for the production version.[1]
Besides adding single-precision floating-point math, Tandy-employee Steve Leininger extended the language to support input/output routines (keyboard, CRT, and reading and writing from cassettes). The language fit within 4 KB of ROM.[2]
Further Development
When the TRS-80 was introduced, three versions of BASIC were announced:
- Level I BASIC
- Level II BASIC - developed by Microsoft and using 12KB of ROM to add string handling, error handling, and dedicated functions
- Level III BASIC - also developed by Microsoft, offering disk commands[3]
The Level I language was not available for the TRS-80 Model II but briefly re-surfaced as the baseline package for the TRS-80 Model III in 1981, selling for $699 compared to the $999 system with Model III BASIC (another Microsoft product). The language was identical to the Model I version but with the addition of commands to output to a printer.[4]
Language Features
Level I BASIC supported the following keywords:[5]
- Commands: NEW, RUN, LIST, CONT (to continue or resume a program from a breakpoint)
- Statements: PRINT, INPUT, READ, DATA, RESTORE, LET
- Structure: GOTO, GOSUB, ON-GOTO, ON-GOSUB, RETURN, IF-THEN [but no ELSE], FOR-NEXT-STEP, STOP, END
- Graphics: CLS, SET, RESET, POINT()
- Functions: ABS(), INT(), RND(), MEM
- Math: + - * /
- Relational operators: < > = <= => <>
- Logical operators: * [AND] + [OR]
Like Palo Alto Tiny BASIC on which it was based, Level I BASIC did not tokenize keywords the way that Microsoft BASICs did and instead - again, like Palo Alto Tiny BASIC did - relied on abbreviations to reduce the amount of memory used by keywords: C. for CONT, E. for END, F. for FOR, G. for GOTO, P. for PRINT, T. for THEN, and so forth (GOS. for GOSUB, REST. for RESTORE).
The language supported single-precision variables A to Z, strings A$ and B$, and the single pre-defined array A(). The language lacked a DIM statement for dimensioning the array, the size of which was determined by available memory not used by the program listing (4 bytes per item).[6]
Lacking many common math functions, the language's user manual provided subroutine listings for square root, exponentiation, exponentials, logarithms, arithmetic sign, and trigonometry functions.[7]
See also
References
- ^ Welsh, David and Welsh, Theresa Priming the Pump: How TRS-80 Enthusiasts Helped Spark the PC Revolution p. 7, Copyright © 2007
- ^ Reed, Matthew. "Level I BASIC". TRS-80.org. Retrieved 27 August 2017.
- ^ Thomas, Wes (Sep–Oct 1977). "Radio Shack's $600 Home Computer". Creative Computing. 3 (5): 94–95.
{{cite journal}}: CS1 maint: date format (link) - ^ Reed, Matthew. "Was there a Level I Model III?". TRS-80.org. Retrieved 27 August 2017.
- ^ Lien, David (1977). User's Manual for Level I (PDF) (First ed.). Fort Worth, TX: Tandy Corporation. pp. 232–233. Retrieved 27 August 2017.
- ^ Lien, David (1977). User's Manual for Level I (PDF) (First ed.). Fort Worth, TX: Tandy Corporation. pp. 123–132. Retrieved 27 August 2017.
- ^ Lien, David (1977). User's Manual for Level I (PDF) (First ed.). Fort Worth, TX: Tandy Corporation. pp. 216–220. Retrieved 27 August 2017.
External links
- TRS-80 Level I BASIC Simulator
- Conklin Systems - He Changed Our World - tribute to the Level I BASIC user manual's personification of the computer