Bob published software, made hardware and wrote books for the Timex/Sinclair computers through his company, Gesso Products.
Bob Orrfelt
Articles (16)
| Title | Author(s) | Publication | Date |
|---|---|---|---|
| 2068 ROM Disassembly Brief news item that Bob Orrfelt of the Peninsula group has disassembled the TS2068 ROM, producing a listing with comments... | Timelinez | January 1985 | |
| 32K RAM 32K RAM in the cartridge port for Timex Portugal Disk Drives. | Timelinez | September - October 1991 | |
| A Mystery Program | Timelinez | ||
| DEF FN: Spectrum-Style User-Defined Functions Reprint of the DEF FN section from the Sinclair Spectrum User’s Guide, supplied by Bob Orrfelt who noted the 2068... | Bob Orrfelt | Timelinez | February 1987 |
| Double Size Letters for Bob Orrfelt’s WP-32 Short programming tip adding double-height letter capability to Bob Orrfelt’s WP-32 word processor for the TS2068. A supplementary BASIC routine... | Walt Gaby | Timelinez | November 1984 |
| Editor’s Corner Describes trip to California, where he met with John Warburton (Sunset Electronics), Jim Howell (A & J Micro), Bob Orrfelt... | Time Designs Magazine | May/June 1985 | |
| EPROMS Are Alive and Well … And Living in Redwood City | Nite-Times News | November 1988 | |
| EPROMS Are Alive and Well… | Timelinez | September - October 1988 | |
| FDD Express: More Letters Letters from Bob Orrfelt about the FDD technical manual he was writing; Jack Dohany about Zebra FDD system; Dennis Bryant... | Update Magazine | July 1988 | |
| Forum Letters to the editor, corrections. Letters from Thomas Griffin, Bob Orrfelt, Dennis Silvestri and Pete Kelly. | SyncWare News | Nov-Dec 1985 | |
| Letters Answers to question from Vince Stimmel in previous issue from Branson Wilcox and William Andrews. Richard Hurd on machine language... | Time Designs Magazine | March/April 1987 | |
| Suggested 2068 ROM Changes | Triangle Sinclair Users Group | ||
| T/S 1000 Digital clock Excerpt from Highfalutin’ Computin’. | Time Designs Magazine | July/August 1986 | |
| T/S Beats IBM! Short article reproducing a floating-point precision benchmark from Fred Gruenberger in Scientific American (April 1984): enter 1.0000001 and square it... | Bob Orrfelt | Timelinez | July 1984 |
| TS Chaos | Timelinez | March 1989 | |
| TS1000 Clone Hardware Analysis Detailed chip-level and hardware analysis of a TS1000-compatible clone, described in the issue’s table of contents as Bob Orrfelt digging... | Bob Orrfelt | Timelinez | May 1987 |
Companies (1)
Products (2)
| Title | Company |
|---|---|
| Cartridge Board Printed circuit board that holds a ROM, RAM or EPROM chip. Use of the cartridge board is documented in the... | Gesso Products |
| Dock It Software and hardware for programming EPROMs suitable for making dock cartridges. | Gesso Products |
Books (2)
| Title | Author(s) | Date |
|---|---|---|
| Highfalutin’ Computin’ with Bob Orrfelt on Your Timex Sinclair 1000 | Bob Orrfelt | 1982 |
| Timex Sinclair 2068 Memory Map and ROM disassembly Appendix to the manual for GESSO EPROM Programmer and EPROM ZAPPER software. | Bob Orrfelt | 1985 |
Downloadable Files (1)
| Title | Type | Company | Download |
|---|---|---|---|
| rWP32 | ROM | Gesso Products | Download |
Documents (4)
- Dock It: EPROM Programmer Manual for the TS2068 Computer with ROM disassembly
- EPROMs are Alive and Well … and Living in Redwood City
- Larken Disk Interface Schematic
- T/S 2040 Printer Schematic