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45-605: The LCD can be tilted for visibility, and can be folded down over the keyboard for transport, unlike computers such as the TRS-80 Model 100 which has the display in the same fixed plane as the keyboard. The HP 110 is similar to the Dulmont Magnum and the Sharp PC-5000 , but all three computers were separately developed by their respective companies. At introduction it had a list price of 2995 US$ (today $ 8780) . In 1985

90-408: A single magnetic flux transition during the period, and ones are encoded as two transitions. For instance, if a byte of data from the original system contains the bits 01000001 , the floppy disk controller will translate this into the series 1 0 1 1 1 0 1 0 1 0 1 0 1 0 1 1 , inserting additional signals in front of every bit to represent the clock. When this signal is then sent to the read/write head,

135-446: A small electromagnet . When the polarity of the magnetic charge on the disk changes, a brief pulse of electricity is induced in the head which is read as a one, any section where the polarity does not change produces a zero. To encode the same letter A, assuming the previous data ended with a zero, a disk would use 01111110. The first zero-to-one transition causes a 1 to be output, the stream of ones following causes no output, and finally

180-462: A steady output clock signal from a noisy input. This was beyond the capabilities of low-cost ICs from the late 1970s, which is why FM remained popular during the early home computer era in the early 1980s. MFM IC's were available, and were used on more expensive platforms like the IBM PC , but using them required the clock recovery to be performed by external hardware, the "data separator". IC manufacturing

225-412: Is due to the hysteresis of the magnetic media, which can lead to an effect known as bit shift that causes the strings of magnetic transition to be stretched out in time. These effects make it difficult to know which bit a particular transition belongs to. To address this problem, disks use some form of clock recovery using additional signals written to the disk. When the data is read, the clock signal

270-425: Is modified using differential Manchester encoding when written to allow clock recovery to address timing effects known as "jitter" seen on disk media. It was introduced on IBM mainframe drives and was almost universal among early minicomputer and microcomputer floppies. In the case of floppies, FM encoding allowed about 80 kB of data to be stored on a 5 + 1 ⁄ 4 -inch disk. IBM began introducing

315-540: Is no object" for 1984. The magazine stated that the $ 2995 price was "surprising modest" for its hardware, Lotus 1-2-3 and other software, and excellent manufacturer support. This computer hardware article is a stub . You can help Misplaced Pages by expanding it . TRS-80 Model 100 The TRS-80 Model 100 is a notebook-sized portable computer introduced in April 1983. It was the first commercially successful notebook computer, known as laptops today, as well as one of

360-426: Is separated out and data bits can then be clearly seen in the signal and be cleanly lined up into the appropriate slots in memory. FM encoding uses a simple system to encode the original data in such a way that every bit of data will contain at least one transition, ensuring there are enough transitions during a given period for a successful clock recovery. To do this, it operates with a basic data period twice that of

405-543: 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 interpreters , variable names were restricted to two characters and all program lines and subroutines were numbered and not named. However,

450-665: The HP ;110 Plus (aka HP Portable Plus and HP 45711A ) was released with a higher-speed internal modem (1200 baud vs. 300 baud), more resident applications, reduced price, and an 80 character by 25 line display, which improved compatibility with desktop software applications. In text mode, the machine supported either a derivation of the 1984 version of the HP Roman-8 character set (in "HP mode") or IBM code page 437 (in "ALT mode"). BYTE in January 1985 acknowledged

495-517: The NEC PC-8201 and PC-8300 were also built on the same Kyocera platform, with some design and hardware differences, which limited their compatibility with the Model 100. The Model 100 was originally marketed as a Micro Executive Work Station (MEWS), although the term did not catch on and was eventually dropped. The 8K and 24K versions sold for US$ 1,099 and US$ 1,399 respectively. The Model 100

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540-557: The FAT (File Allocation Table) file system that was shared with IBM PC computer's at the time, which made it an extremely desired by businesses and government organizations. But, much to the joy of Model 100 owners, there was a second version released late in 1984, known as the TPDD2 , This TPDD2 was labeled as being for the Radio Shack Model 100 and Tandy 102/200 and could store 200 KB on

585-530: The HP ;110's high price, but stated that it was "a computer with true desktop capability and performance well worth its cost for those who need the power". It praised the keyboard, and predicted that the built-in Lotus 1-2-3 "will likely account for more HP 110 sales than any other single feature". Creative Computing said that the 110 was "the overwhelming winner" in the category of notebook portables when "price

630-402: The Model 100 can't handle, where 1924 would be used for 2024 in real life. 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. When introduced,

675-469: The Model 100 to display 40 or 80 column video on an external television set or video monitor via a single RCA video connector. Another popular feature of the Model 100 was its generous options to share files locally or globally via standard telephone lines. The 3 options were: 1) The built-in Hayes compatible 300 baud direct connect modem connected to a telephone line via a standard RJ-25 connector. 2) Thru

720-409: The Model 100, providing a range of customized application software. 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 Y2K bug; the century displayed on the main menu was hard-coded as "19XX". Workarounds exist for this problem. Most people just use 19xx again instead of 20xx, which

765-469: The Model 100. Eventually, the instantly popular alternative to the cassette tape drives were the Tandy Portable Disk Drive (TPDD). The TPDD was introduced in 1983 and was an industry standard RS-232 serial port connected device capable of storing 100 KB of data FM-encoded on a 3.5" single-sided double-density diskette. This TPDD drive used the same DOS 1.0 format, which introduced

810-458: The Mostek MK4116 as a series of 0 and 5 V voltages in the individual capacitors making up the memory. In contrast, magnetic recording systems like floppy disks record this data as a change in magnetic polarity . This is due to the way the data is read and written, using magnetic induction . During reading, the disk is rotating so its surface moves rapidly past the read/write head ,

855-606: The NASA Space Shuttles, and always included program code listed that was submitted by subscribers to the magazine. The Model 100 was sold through Radio Shack stores in the United States and Canada and affiliated dealers in other countries around the world. It became one of the company's most popular models of all time, selling 6,000 units in the first month, with over 100,000 units eventually being sold globally before being discontinued in 1991. The Olivetti M-10 and

900-554: The Radio Shack Model 100 showed the world what a light and small notebook computer could do, which eventually led to the laptop computers that we are all still using today. 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 80 programming language. This

945-512: The acoustic coupler, which were basically suction cups that worked perfectly on pay phone hand receivers and served the same function as the aforementioned RJ-25 connector option. 3) The RS-232 serial port connected to a null modem adapter cable if transferring between computers that were right beside each other. And, with the built-in TELCOM firmware, the Model 100 was an incredibly convenient option for journalists and other professionals to work on

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990-404: The bit, 1 or 0, was encoded by the location of the pulse within the window. 1's were encoded with pulses in the center of the window; 0's with the pulse at the end. Because the accuracy of the transition transition timing is more demanding, MFM requires a more complex solution to recovering the clock signal. Generally this takes the form of a phase locked loop or similar system that will produce

1035-483: The buffer. As each bit of data requires two transition periods in the FM system, it makes use of only half the potential storage capacity of the disk. This led to a series of more advanced encodings that make better use of the available space. The most widely used replacement was modified frequency modulation , or MFM. This system recorded only a single bit in every window, which produced the underlying clock signal. The value of

1080-474: The cost of implementation of a complete drive controller, which consisted largely of a clock, a drive controller chip, a chip to communicate with the host computer, and some buffer memory. Especially popular was the Western Digital FD1771 and its variations. The material above refers to bytes being written to disk, but this is a simplification. In most disks, the only unit of data is the sector , and

1125-462: 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. 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. The Model 100 firmware

1170-541: The default for floating point numbers is double-precision. The ROM also contains a 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. 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

1215-427: The first notebook computers ever released. It featured a keyboard and liquid-crystal display , in a battery-powered package roughly the size and shape of a 1" 3 ring binder. The 224-page, spiral-bound User Manual is nearly the same size as the computer itself and adds to the value of the Model 100, particularly if it still has the pouch in good condition that was included to help protect the manual from damage during

1260-483: The go for the first time and simply transfer files globally with the ease of saving their work on their external storage. In fact, it was common knowledge that the Model 100 was originally used extensively on the NASA space shuttle and was for many years, as NASA frequently showed video at the time of astronauts posing with them on the evening news. Also, Tandy/Radio Shack offered a first of its kind Bar Code Reader Wand, which

1305-473: The header and the data. In the IBM format, this consists of a series of thirteen zeros followed by three hexadecimal A1 's in front of the header and data areas. These are not FM encoded, so the controller can easily identify them on-the-fly. The controller locks onto these signals to find the start of data, which immediately follows the last sync byte. After that, it reads out each eight bits into subsequent bytes in

1350-408: The individual bytes within it have no meaning to the controller. When data is written, the controller is handed a full sector's worth of data and told to write it as a single atomic operation as a series of bits. The controller cannot align the bits with the bytes based solely on the FM information. Thus it is not only the bits within the data that have to be aligned on reading, but the starting point of

1395-461: The last one-to-zero creates the final 1. In addition to the data being stored in patterns that require on-the-fly conversion to and from their internal format, the disk faces additional problems associated with being an analog system – noise, mechanical effects and other issues. In particular, disks suffer from an effect known as jitter due to small changes in timing as the media speeds up and slows down during rotation. One form of unavoidable jitter

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1440-401: The maximum frequency of the recording media. These are known as "clock windows", with up to one clock transition and one data transition per window. Since each bit of data requires two minimum times, FM encoding stores about half the amount that is theoretically possible on that media. FM uses an implementation of the differential Manchester encoding . A zero in the original data is encoded by

1485-468: The mid-1980s. Main memory systems in modern computers store binary information using two different electrical signals, typically voltages. In DRAM for instance, the presence of a voltage over a certain threshold represents a binary one, while any voltage below that value represents a zero. The letter "A" in ASCII is represented as 01000001 in binary, which might be stored in a typical late-1970s DRAM like

1530-454: The more efficient modified frequency modulation , or MFM, starting in 1970. They referred to this format as "double density", with the original FM retroactively becoming "single density". MFM was more difficult to implement and it was not until the early 1980s that low-cost all-in-one MFM floppy drive controllers like the WD1770 emerged. This led to the rapid demise of FM encoding in favor of MFM by

1575-556: The owner's travels. The Model 100 was made by Kyocera , and originally sold in Japan as the Kyotronic 85 . Although a slow seller for Kyocera in Japan, the rights to the machine were purchased by Tandy Corporation and was wildly popular. This popularity was further boosted by there even being a monthly Model 100 magazine that shared stories of people that owned them, including astronauts aboard

1620-401: The polarity will be flipped every time there is a pulse. In this example, if the head was originally in the low state at the end of writing the last data, the leading 1 will flip it to the high state, and the following zero will leave it there. The result is a single transition in that window. The next bit will first flip the state back to low, and then flip it back to high, for two transitions in

1665-477: The portability and simplicity of the Model 100 made it attractive to journalists, who could type about 11 pages of text (if upgraded to the maximum of 32 KB RAM) and then transmit it for electronic editing and production using the built-in modem and TELCOM program. Frequency modulation encoding Frequency modulation encoding , or simply FM , is a method of storing data that saw widespread use in early floppy disk drives and hard disk drives . The data

1710-482: The same 3-1/2" floppy as the previous drive. Also available was the Disk/Video Interface (DVI), which was also released in late 1984. The DVI, which could be bought at local Radio Shack stores with 1 single-sided double-density (SS/DD) 180 KB 5-1/4" disk drive. But, you could also place a special order thru Radio Shack to have your DVI built with 2 SS/DD 5-1/4" disk drives. The custom ordered dual drive DVI

1755-404: The sector's data as a whole. This is not accomplished with the encoding scheme, but the disk format instead. When the controller writes a sector of data, it adds a header section containing information about the data that follows, as well as the address of the sector so it can be found in the future. During the write process, the controller also writes out a series of special "sync bytes" before

1800-414: The window. Encoding these transitions requires the system to accept digital data from the host computer and then re-code it into the underlying FM format. On reading, the system has to separate out the clock signal again and leave only the data bits. Because the FM system is so simple, it could be implemented in single-chip forms using late 1970's semiconductor fabrication techniques. This greatly lowered

1845-404: Was appreciated by many types of industries for a number of reasons, including accounting for, tracking and ordering inventory with a simple swipe of the pen attached to a notebook computer. This was a game changer for companies that came to appreciate the ease and speed this little notebook computer offered them more accurate inventory control while greatly decreasing the cost of labor. In short,

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1890-539: 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

1935-407: Was promoted as being able to run up to 20 hours and maintain memory up to 30 days on a set of four alkaline AA batteries . It could not run from the rechargeable nickel-cadmium batteries available at the time, but a hardware modification was available that made this possible. The Model 100's original form of external storage was the port for a cassette audiotape recorder that would lay alongside

1980-445: Was so rare that The Smithsonian Museum hasn't even got one on display, instead having to settle for the single drive DVI. The monitors used with the DVI were typically in monochrome due to the more desirable and less stressful to the human eye amber screen still being considerably more expensive at the time. But, regardless of the number of drives or color of the screen used, the DVI allowed

2025-472: 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". 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 ROMs can be installed in

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