|Manufacturer||Durango Systems Corp.|
|Type||Personal business computer|
|Release date||September 1978|
|Media||two 100 tpi high-capacity 5.25-inch diskette drives storing 480 KB on each single-sided diskette using group-coded recording (GCR)|
|CPU||5 MHz Intel 8085A|
|Memory||65 KB (up to 196 KB)|
|Storage||40 MB Shugart SA-4006 14-inch winchester|
|Display||9-inch CRT with 64 characters per row by 16 rows or 80 characters per row by 24, based on the Intel 8275 Video display controller|
|Input||keyboard, full stroke, 84 key|
The Durango F-85 was an early personal computer introduced in September 1978 by Durango Systems Corporation, a company started in 1977 by George E. Comstock, John M. Scandalios and Charles L. Waggoner, all formerly of Diablo Systems. The F-85 could run its own multitasking operating system called DX-85M, which included an integral Indexed Sequential (ISAM) file system and per-task file locking, or alternatively CP/M-80. DX-85M utilized a text configuration file named CONFIG.SYS five years before this filename was used for a similar purpose under MS-DOS/PC DOS 2.0 in 1983.
The F-85 used single-sided 5¼-inch 100 tpi diskette drives providing 480 KB utilizing a high-density 4/5 group coded encoding. The machine was using a Western Digital FD1781 floppy disk controller with 77-track Micropolis drives. In later models this was expanded to a double-sided option for 960 KB (946/947 KB formatted[nb 1]) per diskette.
Durango later dropped the "F-85" model name and adopted a user model system, with 700 being the entry model and 950 being the full-featured model.
- The product flyer for the Durango 800 series documents a formatted "on-line capacity" of 1.892 MB for the diskette drives. The system, however, was equipped with two 5¼-inch Micropolis 100 tpi 77-track floppy drives by default, and 1.892 MB is about twice as large as the physical drive capacity documented in various other sources (480 KB per side), therefore, by "on-line capacity" they must have meant the available storage capacity available to users for the combination of two drives.
- Schultz, Brad (1978-10-02). "Business Mini Weighs 65 Pound - What is Durango?". Computerworld. CW Communications, Inc. XII (40): 1, 4. Retrieved 2017-06-13.
- Comstock, George E. (2003-08-13). "Oral History of George Comstock" (PDF). Interview with Hendrie, Gardner. Mountain View, California, USA: Computer History Museum. CHM X2727.2004. Archived (PDF) from the original on 2017-03-23. Retrieved 2017-03-23.
[…] that's how we got Durango Systems started in 1977. And we opened the doors for business I think it was July or August of '77 and began designing a product, one of which is sitting right there. That's the Durango F85 computer […] We were on the startup of Durango, we raised our money and got going and in that case it took us another 15 months to start shipping product […]
- "CI News: Play it again, George?". Computerworld. Computerworld, Inc. XI (47): 64. 1977-11-21. Retrieved 2017-06-13.
- "800 Technical Summary - 800 Series Business Computer System" (PDF). San Jose, CA, USA: Durango Systems, Inc. Archived (PDF) from the original on 2017-03-23. Retrieved 2017-03-23.
- Guzis, Charles P. (October 2006). "The Durango F-85 Computer". Sydex. Archived from the original on 2017-03-23. Retrieved 2017-03-23.
- Guzis, Charles P. (2009-09-13). "Durango GCR". Sydex. Archived from the original on 2017-03-25. Retrieved 2017-03-25.
- "NCC Preview: OEMs at NCC - Micropolis Corp". Computerworld. CW Communications, Inc. XII (22): P/50. 1978-05-28. Retrieved 2017-06-12.
[…] Micropolis has extended the capacity of 5.25-in. floppy disk subsystems via double-sided models with formatted file storage of up to nearly 2 million bytes […] The Megafloppy series also features an intelligent controller that facilitates interconnection of four subsystems to a common host interface for a total on-line storage capacity of more than 15M bytes […] Double-sided versions of the product line will be implemented first in two OEM series - Model 1015 and Model 1055 […] The Model 1015 is an unpackaged drive designed for the manufacturer who integrates floppy disk storage into his own system enclosure. A range of storage capacities from 143,000 to 630,000 bytes per drive is available […] Model 1015 customers have the option of using the Micropolis intelligent controller and Group Code Recording (GCR) method to further expand file space up to 946,000 bytes […] Offering GCR and a microprocessor-based controller as standard features, the Model 1055 5.25-in. floppy has four soft-sectored formats for each of its 77 tracks, yielding a maximum capacity of 1,892,000 bytes of file space on its double-sided version […] An add-on module available for the 1055 is comprised of two read/write heads and two drives, sharing a common controller. The subsystem capacity (formatted) with the module is 3,784,000 bytes […] Up to four 1055s, each with an add-on module, can be daisy-chained to a common host for a maximum on-line storage capacity of more than 15M bytes […]
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