Editing TRS-80 Model 100 (section)

== ROM firmware ==
When first switched on, the Model 100 displays a menu of applications and files and the date and time.{{r|malloy198305}} The [[Read-only memory|ROM]] [[firmware]]-based system boots instantly, and the program that was running when the unit was powered off is ready to use immediately on power-up. Cursor keys are used to navigate the menu and select one of the internal or added application programs, or any data file to be worked upon.

The 32 [[kilobyte]] read-only memory of the Model 100 contains the N82 version of the [[Microsoft BASIC|Microsoft BASIC 80]] programming language. This is similar to other Microsoft BASICs of the time and includes good support for the hardware features of the machine: pixel addressing of the display, support for the internal modem and serial port, monophonic sound, access to tape and RAM files, support for the real-time clock and the bar code reader, and I/O redirection between the machine's various logical devices.  Like previous Microsoft [[BASIC interpreter]]s, variable names were restricted to two characters and all program lines and subroutines were numbered and not named.  However, the default for [[floating point]] numbers is double-precision.

The ROM also contains a [[terminal emulator|terminal program]], TELCOM; an address/phone book organizer, ADDRSS; a to-do list organizer, SCHEDL; and a simple text editor, TEXT. The TELCOM program allows automation of a [[login]] sequence to a remote system under control of the BASIC interpreter.{{r|malloy198305}} As with other [[home computers]] of the era, a vast collection of [[PEEK and POKE]] locations were collected by avid hobbyists.

The Model 100 TEXT editor was noticeably slow in execution, especially for fast [[touch typists]]. This was due partly to the slow 8085 CPU and due partly to the slow response time of the LCD screen. Often after speed-typing a sentence or two, the user would have to wait several seconds for the computer to "catch up". 

A perhaps not well-known but documented feature of TEXT was that it partially supported the [[WordStar]] command interface. The supported commands were the cursor movement and character deletion <Control><alpha> key combinations on the left hand side of the keyboard; the commands for activating Wordstar menus, like the <Ctrl><K> Block menu, were not functional.

[[Easter egg (virtual)|Invisible files]] in the system RAM named "Hayashi" and "Suzuki" commemorate the names of designers Junji Hayashi and Jay Suzuki. Another invisible deleted file named "RickY" refers to Rick Yamashita.<ref>{{cite web
 |url        = http://furukawablog.spaces.live.com/Blog/cns!1pmWgsL289nm7Shn7cS0jHzA!2149.entry
 |title      = The Bill Gates I Know, Volume 12
 |access-date = January 8, 2008
 |author     = Akira Kogawa
 |date       = October 28, 2005
 |language   = ja
}}{{Dead link|date=June 2018 |bot=InternetArchiveBot |fix-attempted=no }} Title and author obtained via Google translation from the original Japanese.</ref> The Model 100 firmware was the last [[Microsoft]] product that [[Bill Gates]] developed personally, along with Suzuki. According to Gates, "part of my nostalgia about this machine is this was the last machine where I wrote a very high percentage of the code in the product".<ref>{{cite interview
 |last         = Gates
 |first        = Bill
 |subject-link = Bill Gates
 |interviewer  = David Allison
 |title        = Bill Gates Interview
 |url          = http://americanhistory.si.edu/comphist/gates.htm#tc35
 |work         = National Museum of American History, Smithsonian Institution
 |access-date  = April 10, 2013
 |archive-date = April 2, 2013
 |archive-url  = https://web.archive.org/web/20130402195548/http://americanhistory.si.edu/comphist/gates.htm#tc35
 |url-status   = live
}}</ref>{{r|malloy198305}}

Added applications and data files are stored in the internal battery-backed RAM; these can be loaded from and stored to an audio cassette tape recorder or external [[floppy disk]] drive. Optional [[Read-only memory|ROMs]] can be installed in the Model 100, providing a range of customized application software.{{r|malloy198305}} Only one optional ROM can be installed at a time. Some commercial software applications for the Model 100 were also distributed on cassette.

The Model 100 ROM has a [[Year 2000 problem|Y2K]] bug; the century displayed on the main menu was [[hard-coded]] as "19XX". [[Workaround]]s exist for this problem.  Since the century of the date is not important for any of the software functions, and the real-time clock hardware in the Model 100 does not have a calendar and requires the day of the week to be set independently of the date, the flaw does not at all impair the usability of the computer; it is cosmetic.