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72-444: Text-based semigraphics , pseudographics , or character graphics is a primitive method used in early text mode video hardware to emulate raster graphics without having to implement the logic for such a display mode. There are two different ways to accomplish the emulation of raster graphics. The first one is to create a low-resolution all points addressable mode using a set of special characters with all binary combinations of

144-426: A function key together. The AAlib open source library provides programs and routines that specialize in translating standard image and video files, such as PNG and WMV , and displaying them as a collection of ASCII characters. This enables a rudimentary viewing of graphics files on text mode systems, and on text mode web browsers such as Lynx . Papertape Punched tape or perforated paper tape

216-492: A read-only memory in some systems. Other systems allow the use of RAM for this purpose, making it possible to redefine the typeface and even the character set for application-specific purposes. The use of RAM-based characters also facilitates some special techniques, such as the implementation of a pixel-graphics frame buffer by reserving some characters for a bitmap and writing pixels directly to their corresponding character memory. In some historical graphics chips, including

288-507: A redisplay everything command, often associated with the Ctrl + L key combination. Text mode video rendering came to prominence in the early 1970s, when video-oriented text terminals started to replace teleprinters in the interactive use of computers. The advantages of text modes as compared to graphics modes include lower memory consumption and faster screen manipulation. At the time text terminals were beginning to replace teleprinters in

360-644: A "0" would be represented by a "N" and a "1" would be represented by a "P", followed by an ending ASCII "F". These ten-character ASCII sequences were separated by one or more whitespace characters , therefore using at least eleven ASCII characters for each byte stored (9% efficiency). The ASCII "N" and "P" characters differed in four bit positions, providing excellent protection from single punch errors. Alternative schemes named BHLF (Begin-High-Low-Finish) and B10F (Begin-One-Zero-Finish) were also available where either "L" and "H" or "0" and "1" were also available to represent data bits, but in both of these encoding schemes,

432-482: A Danish company called Regnecentralen introduced a paper tape reader called RC 2000 that could read 2,000 characters per second; later they increased the speed further, up to 2,500 cps. As early as World War II , the Heath Robinson tape reader , used by Allied codebreakers, was capable of 2,000 cps while Colossus could run at 5,000 cps using an optical tape reader designed by Arnold Lynch. When

504-474: A certain subdivision matrix of the text mode character size; this method is referred to as block graphics , or sometimes mosaic graphics . The second one is to use special shapes instead of glyphs (letters and figures) that appear as if drawn in raster graphics mode, sometimes referred to as semi- or pseudo-graphics ; an important example of this is box-drawing characters . Semigraphical characters (including some block elements) are still incorporated into

576-402: A collection container. A variation on the tape punch was a device called a Chadless Printing Reperforator . This machine would punch a received teleprinter signal into tape and print the message on it at the same time, using a printing mechanism similar to that of an ordinary page printer. The tape punch, rather than punching out the usual round holes, would instead punch little U-shaped cuts in

648-493: A few dozen bytes for each screen update in text mode, as opposed to complex raster graphics remote procedure calls that may require the transmission and rendering of entire bitmaps . The border between text mode and graphical programs can sometimes be fuzzy, especially on the PC's VGA hardware, because many later text mode programs tried to push the model to the extreme by playing with the video controller . For example, they redefined

720-403: A font that are intended to give the impression that a system can support high resolution graphics, while in fact the system operates in text mode. Characters such as box-drawing characters , circles and dots, card symbols like ♠, ♣, ♥ and ♦, and "graphical building block" geometric shapes such as triangles gave such systems that appearance. One of the first systems that used such characters,

792-497: A key stored on paper tape. During the last third of the 20th century, the National Security Agency (NSA) used punched paper tape to distribute cryptographic keys . The eight-level paper tapes were distributed under strict accounting controls and read by a fill device , such as the hand held KOI-18 , that was temporarily connected to each security device that needed new keys. NSA has been trying to replace this method with

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864-466: A limited palette of colors. These attributes can either coexist with the character indices or use a different memory area called color memory or attribute memory . Some text mode implementations also have the concept of line attributes. For example, the VT100-compatible line of text terminals supports the doubling of the width and height of the characters on individual text lines. Depending on

936-507: A more secure electronic key management system ( EKMS ), but as of 2016 , paper tape was apparently still being employed. The paper tape canister is a tamper-resistant container that contains features to prevent undetected alteration of the contents. Acid-free paper or Mylar tapes can be read many decades after manufacture, in contrast with magnetic tape that can deteriorate and become unreadable with time. The hole patterns of punched tape can be decoded by eye if necessary, and even editing of

1008-411: A number of proprietary formats. A much more primitive as well as a much longer high-level encoding scheme was also used, BNPF (Begin-Negative-Positive-Finish), also written as BPNF (Begin-Positive-Negative-Finish). In BNPF encoding, a single byte (8 bits) would be represented by a highly redundant character framing sequence starting with a single uppercase ASCII "B", eight ASCII characters where

1080-513: A program called SVGATextMode is often used with SVGA cards to set up very large console text modes, such as for use with split-screen terminal multiplexers . Many modern programs with a graphical interface simulate the display style of text mode programs, notably when it is important to preserve the vertical alignment of text, e.g., during computer programming . There exist also software components to emulate text mode, such as terminal emulators or command line consoles . In Microsoft Windows ,

1152-435: A tape is possible by manual cutting and splicing. Unlike magnetic tape, magnetic fields such as produced by electric motors cannot alter the punched data. In cryptography applications, a punched tape used to distribute a key can be rapidly and completely destroyed by burning, preventing the key from falling into the hands of an enemy. Reliability of paper tape punching operations was a concern, so that for critical applications

1224-414: A text mode usually uses two distinct areas of memory . Character memory or a pattern table contains a raster font in use, where each character is represented by a dot matrix (a matrix of bits ), so the character memory could be considered as a three-dimensional bit array . Display matrix (a text buffer , screen buffer , or nametable ) tracks which character is in each cell. In the simple case

1296-416: Is a form of data storage device that consists of a long strip of paper through which small holes are punched. It was developed from and was subsequently used alongside punched cards , the difference being that the tape is continuous. Punched cards, and chains of punched cards, were used for control of looms in the 18th century. Use for telegraphy systems started in 1842. Punched tapes were used throughout

1368-517: Is an example, although with a 4:5:4 scheme the distortion effect was minimal. The seminal use of this technology was in the TRS-80 where the only way to get discrete pixels on the screen that could be turned on and off individually, (all points addressable) was by the use of a 2×3 pixel matrix of block graphics. In the case of the TRS-80 these block graphics were not incorporated into a font ROM, as later became

1440-405: Is that they assume monospaced fonts , where every character has the same width on screen, which allows them to easily maintain the vertical alignment when displaying semi-graphical characters. This was an analogy of early mechanical printers which had fixed pitch. This way, the output seen on the screen could be sent directly to the printer maintaining the same format. Depending on the environment,

1512-620: Is the default 80 columns by 25 rows, or 80×25, with 16 colors. This mode was available on practically all IBM and compatible personal computers. Several programs, such as terminal emulators , used only 80×24 for the main display and reserved the bottom row for a status bar . Two other VGA text modes, 80×43 and 80×50, exist but were very rarely used. The 40-column text modes were never very popular outside games and other applications designed for compatibility with television monitors, and were used only for demonstration purposes or with very old hardware. Character sizes and graphical resolutions for

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1584-464: The American Standard Code for Information Interchange (ASCII). This seven-level code was adopted by some teleprinter users, including AT&T ( Teletype ). Others, such as Telex , stayed with the earlier codes. Punched tape was used as a way of storing messages for teletypewriters . Operators typed in the message to the paper tape, and then sent the message at the maximum line speed from

1656-812: The BIOS of any VGA compatible video card, so any PC can display these characters from the moment it is turned on, even when no operating system is yet loaded. Single and double lines are still often drawn with this method when the system uses text mode; for example when running the BIOS setup program. Many of these historical ideas have been adopted into Unicode , in, for example in the Symbols for Legacy Computing , Block Elements , Box Drawing and Geometric Shapes Unicode blocks . For example, an 8×12 pixel character could be divided vertically in two halves and horizontally in three parts, and then assigning "ink" and "background" values to

1728-648: The TMS9918 , the MOS Technology VIC , and the Game Boy graphics hardware, this was actually the canonical way of doing pixel graphics. Text modes often assign attributes to the displayed characters. For example, the VT100 terminal allows each character to be underlined, brightened, blinking or inverse. Color-supporting devices usually allow the color of each character, and often the background color as well, to be selected from

1800-565: The Win32 console usually opens in emulated, graphical window mode. It can be switched to full screen, true text mode and vice versa by pressing the Alt and Enter keys together. This is no longer supported by the WDDM display drivers introduced with Windows Vista. Linux virtual consoles operate in text mode. Most Linux distributions support several virtual console screens, accessed by pressing Ctrl , Alt and

1872-408: The screen buffer can be directly addressable . Programs that display output on remote video terminals must issue special control sequences to manipulate the screen buffer. The most popular standards for such control sequences are ANSI and VT100 . Programs accessing the screen buffer through control sequences may lose synchronization with the actual display so that many text mode programs have

1944-474: The 1970s through the early 1980s, paper tape was commonly used to transfer binary data for incorporation in either mask-programmable read-only memory (ROM) chips or their erasable counterparts EPROMs . A significant variety of encoding formats were developed for use in computer and ROM/EPROM data transfer. Encoding formats commonly used were primarily driven by those formats that EPROM programming devices supported and included various ASCII hex variants as well as

2016-519: The 1970s, the extremely high cost of random-access memory in that period made it exorbitantly expensive to install enough memory for a computer to simultaneously store the current value of every pixel on a screen, to form what would now be called a framebuffer . Early framebuffers were standalone devices which cost tens of thousands of dollars, in addition to the expense of the advanced high-resolution displays to which they were connected. For applications that required simple line graphics but for which

2088-584: The 19th and for much of the 20th centuries for programmable looms, teleprinter communication, for input to computers of the 1950s and 1960s, and later as a storage medium for minicomputers and CNC machine tools . During the Second World War, high-speed punched tape systems using optical readout methods were used in code breaking systems. Punched tape was used to transmit data for manufacture of read-only memory chips. Perforated paper tapes were first used by Basile Bouchon in 1725 to control looms. However,

2160-574: The 19th century for controlling looms. Many professional embroidery operations still refer to those individuals who create the designs and machine patterns as punchers even though punched cards and paper tape were eventually phased out in the 1990s. In 1842, a French patent by Claude Seytre described a piano playing device that read data from perforated paper rolls . By 1900, wide perforated music rolls for player pianos were used to distribute popular music to mass markets. In 1846, Alexander Bain used punched tape to send telegrams . This technology

2232-458: The 7F hex "byte" which was considered to be the "DEL" or "rub-out" character ). The assignment in ASCII of the rub-out character (to the code point 127) led designers of VDUs to use "rub-out" for a character square filled with "ink", which was often used to represent the cursor. Other examples of systems that relied on the use of block graphics are: Semigraphical characters are also characters in

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2304-492: The Sinclair ZX81 ). Sometimes the text semigraphical characters are simply incorporated into the systems font-set, sometimes special video hardware is used to directly convert the bit-pattern from video memory into the pixels. In rare cases a character matrix was not dividable vertically by three, for example in an 8×8 matrix the mosaic is sometimes divided so that it uses a 3:2:3 scan line scheme. The Galaksija's graphics mode

2376-611: The canonical example that others followed, was the Commodore PET , which had many of them within its PETSCII font set. The original PET relied to such a degree on these characters that it printed them on its keyboard, as can be seen here, an example that other systems soon copied. Another good example of a system that relied on semigraphical characters is the venerable Sharp MZ80K , which had no high-resolution graphics, nor reprogrammable characters, but relied fully on an extended font set with many pseudo graphical characters. With these it

2448-466: The character set in order to create custom semi-graphical characters, or even created the appearance of a graphical mouse pointer by redefining the appearance of the characters over which the mouse pointer was shown at a given time. Text mode rendering with user-defined characters has also been useful for 2D computer and video games because the game screen can be manipulated much faster than with pixel-oriented rendering. A video controller implementing

2520-466: The characters in a full block graphics font set are the logical inverse of the other half of the font set. Other tricks that were used to decrease the number of needed characters, was to use a space for the "all bits are zero" character, and to use character 7F hex for the "all bits are on" character, as character 7F hex (decimal 127) was often defined as an "all pixels on" character (this was because when using papertape punching out all seven holes, created

2592-536: The display matrix can be just a matrix of code points (so named character pointer table ), but it usually stores for each character position not only a code, but also attributes . In the case of raster scan output, which is the most common for computer monitors, the corresponding video signal is made by the character generator , a special electronic unit similar to devices with the same name used in video technology . The video controller has two registers : scan line counter and dot counter, serving as coordinates in

2664-431: The elements of the matrix in a binary pattern, corresponding to the binary sequence of the position in the font table of a 2×3 block mosaic matrix of so-called squots (square dots) or sextants . Less often used versions use a 1×6 "matrix", in which case these six "pixels" are sometimes referred to as sixels . But dividing an 8×8 character in 2×2 "pixels" called quadrants was also common (it was, for example, used in

2736-474: The expense of a framebuffer could not be justified, vector displays were a popular workaround. But there were many computer applications (e.g., data entry into a database) for which all that was required was the ability to render ordinary text in a quick and cost-effective fashion to a cathode-ray tube . Text mode avoids the problem of expensive memory by having dedicated display hardware re-render each line of text from characters into pixels with each scan of

2808-451: The extended VESA -compatible Super VGA text modes are manufacturer-dependent. Also on these display adapters, available colors can be halved from 16 to 8 when a second customized character set is employed (giving a total repertoire of 512 —instead the common 256— different graphic characters simultaneously displayed on the screen). Some cards (e.g. S3 ) supported custom very large text modes, like 100×37 or even 160×120. In Linux systems,

2880-466: The first minicomputers were being released, most manufacturers turned to the existing mass-produced ASCII teleprinters (primarily the Teletype Model 33 , capable of ten ASCII characters per second throughput) as a low-cost solution for keyboard input and printer output. The commonly specified Model 33 ASR included a paper tape punch/reader, where ASR stands for "Automatic Send/Receive" as opposed to

2952-489: The graphics adapter used, a variety of text modes are available on IBM PC–compatible computers. They are listed on the table below: MDA text could be emphasized with bright, underline, reverse and blinking attributes. Video cards in general are backward compatible, i.e. EGA supports all MDA and CGA modes, VGA supports MDA, CGA and EGA modes. By far the most common text mode used in DOS environments, and initial Windows consoles,

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3024-423: The holes and was directed into certain mechanisms of the caster. The system went into commercial use in 1897 and was in production well into the 1970s, undergoing several changes along the way. In the 21st century, punched tape is obsolete except among hobbyists . In computer numerical control (CNC) machining applications, though paper tape has been superseded by digital memory , some modern systems still measure

3096-455: The holes by means of blunt spring-loaded mechanical sensing pins, which easily pushed the paper flaps out of the way. Text was encoded in several ways. The earliest standard character encoding was Baudot , which dates back to the 19th century and had five holes. The Baudot code was superseded by modified five-hole codes such as the Murray code (which added carriage return and line feed ) which

3168-490: The message with a tape reader, the line could operate continuously rather than depending on continuous "on-line" typing by a single operator. Typically, a single 75 WPM line supported three or more teletype operators working offline. Tapes punched at the receiving end could be used to relay messages to another station. Large store and forward networks were developed using these techniques. Paper tape could be read into computers at up to 1,000 characters per second. In 1963,

3240-511: The narrower width of the tape were generally the least significant bits when the code was represented as numbers in a digital system. Many early machines used oiled paper tape, which was pre-impregnated with a light machine oil , to lubricate the reader and punch mechanisms. The oil impregnation usually made the paper somewhat translucent and slippery, and excess oil could transfer to clothing or any surfaces it contacted. Later optical tape readers often specified non-oiled opaque paper tape, which

3312-526: The norm, but were generated directly from the logic pattern of six bits from the video RAM using a dedicated circuit made from logic gates . An earlier system using the same pseudo-graphics array of a 2 by 3 matrix was the Video Terminal Interface (VTI) of the Poly-88 by polymorphic systems , an S-100 bus based system predating the TRS-80. If the system also supported color, the color resolution of

3384-639: The order of 35–40% (e.g., 36% from 44 8-bit ASCII characters being needed to represent sixteen bytes of binary data per frame). In the 1970s, computer-aided manufacturing equipment often used paper tape. A paper tape reader was smaller and less expensive than Hollerith card or magnetic tape readers, and the medium was reasonably reliable in a manufacturing environment. Paper tape was an important storage medium for computer-controlled wire-wrap machines, for example. Premium black waxed and lubricated long-fiber papers, and Mylar film tape were developed so that heavily used production tapes would last longer. In

3456-516: The paper tape could be put into a paper tape reader on the Linotype and it would create the lead slugs without the operator re-typing the stories. This also allowed newspapers to use devices, such as the Friden Flexowriter , to convert typing to lead type via tape. Even after the demise of Linotype and hot lead typesetting, many early phototypesetter devices utilized paper tape readers. If an error

3528-519: The paper tapes were expensive to create, fragile, and difficult to repair. By 1801, Joseph Marie Jacquard had developed machines to create paper tapes by tying punched cards in a sequence for Jacquard looms . The resulting paper tape, also called a "chain of cards", was stronger and simpler both to create and to repair. This led to the concept of communicating data not as a stream of individual cards, but as one "continuous card" (or tape). Paper tapes constructed from punched cards were widely used throughout

3600-451: The paper, so that no chad would be produced; the "hole" was still filled with a little paper trap-door. By not fully punching out the hole, the printing on the paper remained intact and legible. This enabled operators to read the tape without having to decipher the holes, which would facilitate relaying the message on to another station in the network. Also, there was no "chad box" to empty from time to time. A disadvantage to this technology

3672-417: The paper-hungry teleprinters they were supposed to replace. Another advantage of text mode is that it has relatively low bandwidth requirements in remote terminal use. Thus, a text mode remote terminal can necessarily update the screen much faster than a graphics mode remote terminal linked to the same amount of bandwidth (and in turn will seem more responsive), since the remote server may only need to transmit

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3744-399: The punchless/readerless KSR – Keyboard Send/Receive and RO – Receive Only models. As a side effect, punched tape became a popular medium for low-cost minicomputer data and program storage, and it was common to find a selection of tapes containing useful programs in most minicomputer installations. Faster optical readers were also common. Binary data transfer to or from these minicomputers

3816-414: The resulting pixels was normally equal to the text resolution, often leading to attribute clash as the color of a pixel could not be changed on a per pixel basis, but only to one "ink", and one "background" color for all pixels within a character position. Sometimes the number of characters in the font, dedicated to block graphics, could be halved if the system also supported an "invert" attribute, as half

3888-400: The screen by the cathode ray. In turn, the display hardware needs only enough memory to store the pixels equivalent to one line of text (or even less) at a time. Thus, the computer's screen buffer only stores and knows about the underlying text characters (hence the name "text mode") and the only location where the actual pixels representing those characters exist as a single unified image is

3960-400: The screen dot matrix. Each of them must be divided by corresponding glyph size to obtain an index in the display matrix; the remainder is an index in glyph matrix. If glyph size equals to 2 , then it is possible just to use n low bits of a binary register as an index in glyph matrix, and the rest of bits as an index in the display matrix — see the scheme. The character memory resides in

4032-478: The screen itself, as viewed by the user (thanks to the phenomenon of persistence of vision ). For example, a screen buffer sufficient to hold a standard grid of 80 by 25 characters requires at least 2,000 bytes. Assuming a monochrome display , 8 bits per byte, and a standard size of 8 times 8 bits for each character, a framebuffer large enough to hold every pixel on the resulting screen would require at least 128,000 bits, 16,000 bytes, or just under 16 kilobytes. By

4104-804: The size of stored CNC programs in feet or meters, corresponding to the equivalent length if the data were actually punched on paper tape. Data was represented by the presence or absence of a hole at a particular location. Tapes originally had five rows of holes for data across the width of the tape. Later tapes had more rows. A 1944 electro-mechanical programmable calculating machine, the Automatic Sequence Controlled Calculator or Harvard Mark I , used paper tape with 24 rows, The IBM Selective Sequence Electronic Calculator (SSEC) used paper tape with 74 rows. Australia's 1951 electronic computer, CSIRAC , used 3-inch (76 mm) wide paper tape with twelve rows. A row of smaller sprocket holes

4176-521: The standards of modern computers, these may seem like trivial amounts of memory, but to put them in context, the original Apple II was released in 1977 with only four kilobytes of memory and a price of $ 1,300 in U.S. dollars (at a time when the minimum wage in the United States was only $ 2.30 per hour). Furthermore, from a business perspective, the business case for text terminals made no sense unless they could be produced and operated more cheaply than

4248-410: The tape. This permitted the operator to prepare the message "off-line" at the operator's best typing speed, and permitted the operator to correct any error prior to transmission. An experienced operator could prepare a message at 135 words per minute (WPM) or more for short periods. The line typically operated at 75 WPM, but it operated continuously. By preparing the tape "off-line" and then sending

4320-415: The tape. This process created " chad ", or small circular pieces of paper. Managing the disposal of chad was an annoying and complex problem, as the tiny paper pieces had a tendency to escape containment and to interfere with the other electromechanical parts of the teleprinter equipment. Chad from oiled paper tape was particularly problematic, as it tended to clump and build up, rather than flowing freely into

4392-418: The two data-bearing ASCII characters differ in only one bit position, providing very poor single punch error detection. NCR of Dayton, Ohio , made cash registers around 1970 that would punch paper tape. Sweda made similar cash registers around the same time. The tape could then be read into a computer and not only could sales information be summarized, billings could be done on charge transactions. The tape

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4464-573: The user by using command-line interfaces and text user interfaces . Many character sets used in text mode applications also contain a limited set of predefined semi-graphical characters usable for drawing boxes and other rudimentary graphics, which can be used to highlight the content or to simulate widget or control interface objects found in GUI programs. A typical example is the IBM code page 437 character set. An important characteristic of text mode programs

4536-607: Was adopted by Charles Wheatstone in 1857 for the Wheatstone system used for the automated preparation, storage and transmission of data in telegraphy. In the 1880s, Tolbert Lanston invented the Monotype typesetting system , which consisted of a keyboard and a composition caster . The tape, punched with the keyboard, was later read by the caster, which produced lead type according to the combinations of holes in up to 31 positions. The tape reader used compressed air, which passed through

4608-406: Was also used for inventory tracking, recording department and class numbers of items sold. Punched paper tape was used by the newspaper industry until the mid-1970s or later. Newspapers were typically set in hot lead by devices like Linotype machines . With the wire services coming into a device that would punch paper tape, rather than the Linotype operator having to retype all the incoming stories,

4680-408: Was always punched to be used to synchronize tape movement. Originally, this was done using a wheel with radial teeth called a sprocket wheel . Later, optical readers made use of the sprocket holes to generate timing pulses. The sprocket holes were slightly closer to one edge of the tape, dividing the tape into unequal widths, to make it unambiguous which way to orient the tape in the reader. The bits on

4752-692: Was developed into the Western Union code which was further developed into the International Telegraph Alphabet No. 2 (ITA 2), and a variant called the American Teletypewriter code (USTTY). Other standards, such as Teletypesetter (TTS), FIELDATA and Flexowriter , had six holes. In the early 1960s, the American Standards Association led a project to develop a universal code for data processing, which became

4824-441: Was found at one position on the six-level tape, that character could be turned into a null character to be skipped by punching out the remaining non-punched positions with what was known as a “chicken plucker". It looked like a strawberry stem remover that, pressed with thumb and forefinger, could punch out the remaining positions, one hole at a time. Vernam ciphers were invented in 1917 to encrypt teleprinter communications using

4896-469: Was less prone to depositing oily debris on the optical sensors and causing read errors. Another innovation was fanfold paper tape, which was easier to store compactly and less prone to tangling, as compared to rolled paper tape. For heavy-duty or repetitive use, polyester Mylar tape was often used. This tough, durable plastic film was usually thinner than paper tapes, but could still be used in many devices originally designed for paper media. The plastic tape

4968-535: Was often accomplished using a doubly encoded technique to compensate for the relatively high error rate of punches and readers. The low-level encoding was typically ASCII, further encoded and framed in various schemes such as Intel Hex , in which a binary value of "01011010" would be represented by the ASCII characters "5A". Framing, addressing and checksum (primarily in ASCII hex characters) information helped with error detection. Efficiencies of such an encoding scheme are on

5040-584: Was sometimes transparent, but usually was aluminized to make it opaque enough for use in high-speed optical readers. Tape for punching was usually 0.00394 inches (0.100 mm) thick. The two most common widths were 11 ⁄ 16 inch (17 mm) for five bit codes, and 1 inch (25 mm) for tapes with six or more bits. Hole spacing was 0.1 inches (2.5 mm) in both directions. Data holes were 0.072 inches (1.8 mm) in diameter; sprocket feed holes were 0.046 inches (1.2 mm). Most tape-punching equipment used solid circular punches to create holes in

5112-602: Was still possible to generate games that looked like the system had high-resolution graphics. Some of the systems that had a programmable font set, but did not have a real high resolution raster graphics hardware, came with default character sets to be uploaded in character set RAM, and these sets often incorporated the ideas mentioned here, although it was often also the case that dedicated semigraphical characters were defined as needed. Examples of systems that relied heavily on semigraphical characters for their graphics are: Text mode Text mode applications communicate with

5184-471: Was that, once punched, chadless tape did not roll up well for storage, because the protruding flaps of paper would catch on the next layer of tape so it could not be coiled up tightly. Another disadvantage that emerged in time, was that there was no reliable way to read chadless tape in later high-speed readers which used optical sensing. However, the mechanical tape readers used in most standard-speed equipment had no problem with chadless tape, because they sensed

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