Sdltrs is a Radio Shack TRS-80 Model I/III/4/4P emulator for.Announced at a press conference in August 3, 1977, the Tandy TRS-80 Model I was Tandy's entry into the home computer market, meant to compete head on against the Commodore PET 2001 and the Apple II. Technical DetailsThe Big List of TRS SDLTRS - a TRS-80 Emulator for Mac OS X, Windows, and Linux. In fact, most short-cut keys wont work as the emulator needs to intercept most key presses. Oh, and, sorry in advance, the backspace button wont leave the page because it is too useful for deleting characters. Note that the backslash () key is the TRS-80 clear key, needed to start Super Nova.It is also the only one.Tandy ended up selling 10,000 the first month and 55,000 its first year. TRS-80 is a fast TRS-80 emulator for the Mac. Instead of using the X-Window system for graphics, it uses the portable SDL library. It has been ported from Tim Mann's excellent X-Windows UNIX emulator xtrs. Sdltrs is a Radio Shack TRS-80 Model I/III/4/4P emulator for Macintosh OSX, Windows, and Linux. Company management was unsure of the computer's market appeal, and intentionally kept the initial production run to 3,000 units so that, if the computer failed to sell, it could at least be used for accounting purposes within the chain's 3,000 stores.SDLTRS.The basic model originally shipped with 4k of RAM, and later 16k.Model I/II/III/4 Emulator for Windows (Runs on MAC and OSX Catalina under. It includes lower case, the real time clock, hi-res graphics, serial port, parallel printer, mouse, cassette, sound and music output (requires OSS), 5 and 8 floppy disk drives in single and double density, and even hard disk drives.The Model I looked like a very thick keyboard (like the later Commodore VIC-20) and used a Zilog Z80 processor. It has been ported from Tim Manns excellent X-Windows UNIX.xtrs is a Radio Shack TRS-80 Model I/III/4/4P emulator for Unix and the X Window System.
Because of bandwidth problems in the interface card that replaced the TV's tuner, the display would lose horizontal sync if large areas of white were displayed a simple hardware fix (involving less than half an hour's work) could be applied to correct that.The video hardware could only display text at 64 or 32 characters wide by 16 lines resolution in upper case. The actual color of the system was light bluish (the standard "P4" phosphor used in black-and white televisions), and green and amber filters or replacement tubes, to make the display easier on the eyes, were a common after market item. Eventually, this was added to a later ROM revision.It was accompanied by a white on black display, which was a modified RCA XL-100 Black and White television. A Keyboard De-Bounce tape was distributed, which slowed down polling of the keyboard to compensate. Create a plug in for mac powerpointThis was not as bad as a Timex ZX81, where the entire screen flickered, and many software authors were able to minimize this effect. Writing to the screen directly (rather than by using the runtime calls in the BASIC ROMs) caused "snow" on the screen because no bus arbitration logic was used to arbitrate between CPU writes to the screen RAM and display logic reads from the same RAM. Aftermarket Lowercase upgrades (which were very popular and referred to as the "Electric Pencil Modification" after a popular Wordprocessor of the time) added the 8th bit and through use of a switch, one could go back and forth between the original 7 bit or 8 bit video.Primitive graphics ("text semigraphics," rather than a true bitmap) could be displayed because 64 characters of the character set displayed as a grid of 2x3 blocks. ![]() The Percom Doubler added the ability to boot and use Double Density Floppies (they provided their own modified TRSDOS called DoubleDOS), and included the Data Separator. This could be overcome by using special cabling, and by doing a "dummy" write to the cassette port while triggering the printer.A Data Separator and/or a Double Density disk controller (based on the WD 1791 chip) were made available by Percom (a Texas Peripheral Vendor), LNW, Tandy and others. Unfortunately, it was incompatible with both the final, buffered version of the E/I, and with the "heartbeat" interrupt used for the real-time clock under Disk BASIC. Level I BASIC fit into 4K ROM, and Level II BASIC fit into 12K ROM. Or one could purchase factory-made "flippies," or use the back side for Apple systems (as some software publishers of the era did).There were two versions of the BASIC programming language produced for the Model I. On the other hand, the use of index-sync meant that in order to turn a floppy disk into a " flippy," it was necessary not only to cut a second write-enable notch, but also to punch a second index hole window in the jacket (at great risk to the disk inside). The combination of 40 tracks, double-density, and index-sync gave a maximum capacity of 180 kilobytes per single-sided floppy disk, considerably higher than most other systems of the era. Trs 80 Emulator Free Tiny BasicThis added most of the functions in the full 16K version of Basic.The first models of the Model I also had problems reading from the cassette drives. It was a cut down version of the 16K Extended BASIC, since the Model I had 12K of ROM space.See "TRS-80 architect.htm" ( ) (TRS-80 architect reminisces about design project) for a complete discussion.The Disk Based BASIC added the ability to perform disk I/O, and in some cases (NewDos/80, MultiDOS, DosPlus, LDOS) added powerful sorting, searching, full screen editing, and other features.Microsoft also marketed a tape-cassette based enhanced BASIC called Level III BASIC. Level II was further enhanced when a disk system was added, and the Disk Based BASIC was loaded.Level I Basic was Li-Chen Wang's free Tiny Basic, hacked by Radio Shack to add functionality.Level II BASIC was licensed from Microsoft. Level II introduced double precision floating point support and had a much wider set of commands. It was not an upgrade of the Model I, but an entirely different system. There was also the Dutch Aster CT-80.Tandy sold the LNW-80 computers with a Tandy Brand in Mexico.In 1980, Tandy produced the Model II which was designed as a business machine. EACA in Hong Kong made a clone that was marketed around the world under different names, in Australia and New Zealand it was the Dick Smith System-80in ( ) North America it was PMC-80, and in Western Europe it was Video Genie and later Genie I and II (It had a different expansion bus so EACA also had its own Expansion Interface). The LNW-80 Model's I/II and Team Computers (LNW also produced an alternate version of the Expansion Interface). The LOBO Max-80 (Lobo also produced their own version of the Expansion Interface). The ROMS in later models were modified to correct this.Many clones of the TRS-80 Model I came on the market. In fact, the Model I's radiated so much RFI (Radio Frequency Interference) that many game companies made their games so you could put an AM radio next to the computer and use the interference to get sounds.The successor to the Model III was the Model 4 (April 1983), which included the capability to run CP/M. With the introduction of the Model III, Model I production was eventually discontinued as the Model I's did not comply with new FCC regulations regarding radio interference. The improvements of the Model III included built-in lower case, a better keyboard, and a faster Z-80 processor. ![]()
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