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61-629: CTSS was developed at the MIT Computation Center ("Comp Center"). CTSS was first demonstrated on MIT's modified IBM 709 in November 1961. The hardware was replaced with a modified IBM 7090 in 1962 and later a modified IBM 7094 called the "blue machine" to distinguish it from the Project MAC CTSS IBM 7094. Routine service to MIT Comp Center users began in the summer of 1963 and was operated there until 1968. A second deployment of CTSS on

122-400: A braille embosser (printer) or a refreshable braille display (screen). Braille has been extended to an 8-dot code , particularly for use with braille embossers and refreshable braille displays. In 8-dot braille the additional dots are added at the bottom of the cell, giving a matrix 4 dots high by 2 dots wide. The additional dots are given the numbers 7 (for the lower-left dot) and 8 (for

183-566: A slate and stylus , a braille writer , an electronic braille notetaker or with the use of a computer connected to a braille embosser . Braille is named after its creator, Louis Braille , a Frenchman who lost his sight as a result of a childhood accident. In 1824, at the age of fifteen, he developed the braille code based on the French alphabet as an improvement on night writing . He published his system, which subsequently included musical notation , in 1829. The second revision, published in 1837,

244-526: A word space . Dot configurations can be used to represent a letter, digit, punctuation mark, or even a word. Early braille education is crucial to literacy, education and employment among the blind. Despite the evolution of new technologies, including screen reader software that reads information aloud, braille provides blind people with access to spelling, punctuation and other aspects of written language less accessible through audio alone. While some have suggested that audio-based technologies will decrease

305-459: A greater number of symbols. (See Gardner–Salinas braille codes .) Luxembourgish Braille has adopted eight-dot cells for general use; for example, accented letters take the unaccented versions plus dot 8. Braille was the first writing system with binary encoding . The system as devised by Braille consists of two parts: Within an individual cell, the dot positions are arranged in two columns of three positions. A raised dot can appear in any of

366-405: A maximum of 42 cells per line (its margins are adjustable), and typical paper allows 25 lines per page. A large interlining Stainsby has 36 cells per line and 18 lines per page. An A4-sized Marburg braille frame, which allows interpoint braille (dots on both sides of the page, offset so they do not interfere with each other), has 30 cells per line and 27 lines per page. A Braille writing machine

427-514: A maximum of six-characters long. Both support linked files. MIT Computation Center The MIT Computation Center was organized in 1956 as a 10-year joint venture between the Massachusetts Institute of Technology and IBM to provide computing resources for New England universities. As part of the venture, IBM installed an IBM 704 , which remained at MIT until 1960. After the successful launch of Sputnik on October 4, 1957,

488-580: A paper about that system at the Spring Joint Computer Conference . Robert C. Daley, Peter R. Bos and at least 6 other programmers implemented the operating system, partly based on the Fortran Monitor System . The system used an IBM 7090 , modified by Herbert M. Teager , with added 3 Flexowriters for user consoles, and maybe a timer . Each of the 3 users had two tape units , one for the user's file directory, and one for dumping

549-509: A quantum time unit 200 ms, was controlled by a multilevel feedback queue . It also had some special memory-management hardware, a clock interrupt, and the ability to trap certain instructions. CTSS at first had only an assembler, FAP , and a compiler, MAD. Also, Fortran II code could be translated into MAD code by using MADTRN. Later half of the system was written in MAD. Later there were other programming languages including COMIT II , LISP 1.5 and

610-722: A separate IBM 7094 that was received in October 1963 (the "red machine") was used early on in Project MAC until 1969 when the red machine was moved to the Information Processing Center and operated until July 20, 1973. CTSS ran on only those two machines; however, there were remote CTSS users outside of MIT including ones in California, South America, the University of Edinburgh and the University of Oxford . John Backus said in

671-611: A space-saving mechanism; and grade 3  – various non-standardized personal stenographies that are less commonly used. In addition to braille text (letters, punctuation, contractions), it is also possible to create embossed illustrations and graphs, with the lines either solid or made of series of dots, arrows, and bullets that are larger than braille dots. A full braille cell includes six raised dots arranged in two columns, each column having three dots. The dot positions are identified by numbers from one to six. There are 64 possible combinations, including no dots at all for

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732-601: A system much more like shorthand. Today, there are braille codes for over 133 languages. In English, some variations in the braille codes have traditionally existed among English-speaking countries. In 1991, work to standardize the braille codes used in the English-speaking world began. Unified English Braille (UEB) has been adopted in all seven member countries of the International Council on English Braille (ICEB) as well as Nigeria. For blind readers, braille

793-469: A text interfered with following the alignment of the letters, and consequently made texts more difficult to read than Braille's more arbitrary letter assignment. Finally, there are braille scripts that do not order the codes numerically at all, such as Japanese Braille and Korean Braille , which are based on more abstract principles of syllable composition. Texts are sometimes written in a script of eight dots per cell rather than six, enabling them to encode

854-409: A version of ALGOL . Each user had their own directory , and there were also shared directories for groups of people with the same "problem number". Each file had two names, the second indicating its type as did the extension in later system. At first, each file could have one of four modes: temporary, permanent, read-only class 1, and read-only class 2. Read-only class 1 allowed the user to change

915-592: Is a typewriter with six keys that allows the user to write braille on a regular hard copy page. The first Braille typewriter to gain general acceptance was invented by Frank Haven Hall (Superintendent of the Illinois School for the Blind ), and was presented to the public in 1892. The Stainsby Brailler, developed by Henry Stainsby in 1903, is a mechanical writer with a sliding carriage that moves over an aluminium plate as it embosses Braille characters. An improved version

976-517: Is an independent writing system, rather than a code of printed orthography. Braille is derived from the Latin alphabet, albeit indirectly. In Braille's original system, the dot patterns were assigned to letters according to their position within the alphabetic order of the French alphabet of the time, with accented letters and w sorted at the end. Unlike print, which consists of mostly arbitrary symbols,

1037-530: Is dot 5, which combines with the first letter of words. With the letter ⠍ m , the resulting word is ⠐ ⠍ mother . There are also ligatures ("contracted" letters), which are single letters in braille but correspond to more than one letter in print. The letter ⠯ and , for example, is used to write words with the sequence a-n-d in them, such as ⠛ ⠗ ⠯ grand . Most braille embossers support between 34 and 40 cells per line, and 25 lines per page. A manually operated Perkins braille typewriter supports

1098-399: Is extended by adding the decade dots, whereas in the fifth decade it is extended by shifting it downward. Originally there had been nine decades. The fifth through ninth used dashes as well as dots, but they proved to be impractical to distinguish by touch under normal conditions and were soon abandoned. From the beginning, these additional decades could be substituted with what we now know as

1159-555: Is read as capital 'A', and ⠼ ⠁ as the digit '1'. Basic punctuation marks in English Braille include: ⠦ is both the question mark and the opening quotation mark. Its reading depends on whether it occurs before a word or after. ⠶ is used for both opening and closing parentheses. Its placement relative to spaces and other characters determines its interpretation. Punctuation varies from language to language. For example, French Braille uses ⠢ for its question mark and swaps

1220-590: The American Printing House for the Blind to print the first braille edition of a book produced from teletypesetter input, only a few weeks after the ink-print version. The following year, on CTSS, a demonstration of printing mathematical tables in braille was shown. A short FORTRAN II program was written to produce a conversion table from inches to millimeters in braille via the BRAILLEMBOSS braille page printer. The Intrex Retrieval System ran on CTSS. Intrex

1281-516: The IBM 704 as official tracker for the SAO occurred at 7AM on October 11, 1957. Braille Braille ( / ˈ b r eɪ l / BRAYL , French: [bʁɑj] ) is a tactile writing system used by people who are visually impaired . It can be read either on embossed paper or by using refreshable braille displays that connect to computers and smartphone devices. Braille can be written using

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1342-453: The slate and stylus is a portable writing tool, much like the pen and paper for the sighted. Errors can be erased using a braille eraser or can be overwritten with all six dots ( ⠿ ). Interpoint refers to braille printing that is offset, so that the paper can be embossed on both sides, with the dots on one side appearing between the divots that form the dots on the other. Using a computer or other electronic device, Braille may be produced with

1403-437: The 1954 summer session at MIT that "By time sharing, a big computer could be used as several small ones; there would need to be a reading station for each user". Computers at that time, like IBM 704 , were not powerful enough to implement such system, but at the end of 1958, MIT's Computation Center nevertheless added a typewriter input to its 704 with the intent that a programmer or operator could "obtain additional answers from

1464-422: The French order of the decade was u v x y z ç é à è ù ( ⠥ ⠧ ⠭ ⠽ ⠵ ⠯ ⠿ ⠷ ⠮ ⠾ ). The next ten letters, ending in w , are the same again, except that for this series position 6 (purple dot in the bottom right corner of the cell in the table above) is used without a dot at position 3. In French braille these are the letters â ê î ô û ë ï ü œ w ( ⠡ ⠣ ⠩ ⠹ ⠱ ⠫ ⠻ ⠳ ⠪ ⠺ ). W had been tacked onto

1525-465: The addition of a dot at position 3 (red dots in the bottom left corners of the cells in the table below): ⠅ ⠇ ⠍ ⠝ ⠕ ⠏ ⠟ ⠗ ⠎ ⠞ : The next ten letters (the next " decade ") are the same again, but with dots also at both position 3 and position 6 (green dots in the bottom rows of the cells in the table above). Here w was left out as it was not part of the official French alphabet in Braille's time;

1586-401: The alphabet – thus the code was unable to render the orthography of the words. Second, the 12-dot symbols could not easily fit beneath the pad of the reading finger. This required the reading finger to move in order to perceive the whole symbol, which slowed the reading process. (This was because Barbier's system was based only on the number of dots in each of two 6-dot columns, not

1647-460: The braille alphabet follows a logical sequence. The first ten letters of the alphabet, a – j , use the upper four dot positions: ⠁ ⠃ ⠉ ⠙ ⠑ ⠋ ⠛ ⠓ ⠊ ⠚ (black dots in the table below). These stand for the ten digits 1 – 9 and 0 in an alphabetic numeral system similar to Greek numerals (as well as derivations of it, including Hebrew numerals , Cyrillic numerals , Abjad numerals , also Hebrew gematria and Greek isopsephy ). Though

1708-546: The braille letters according to the sort order of the print alphabet being transcribed; and reassigning the letters to improve the efficiency of writing in braille. Under international consensus, most braille alphabets follow the French sorting order for the 26 letters of the basic Latin alphabet , and there have been attempts at unifying the letters beyond these 26 (see international braille ), though differences remain, for example, in German Braille . This unification avoids

1769-540: The chaos of each nation reordering the braille code to match the sorting order of its print alphabet, as happened in Algerian Braille , where braille codes were numerically reassigned to match the order of the Arabic alphabet and bear little relation to the values used in other countries (compare modern Arabic Braille , which uses the French sorting order), and as happened in an early American version of English Braille, where

1830-406: The core (program in memory). There was also one tape unit for the system commands, there were no disk drives. The memory was 27 k words (36-bit words) for users, and 5 k words for the supervisor (operating system). The input from the consoles was written to the buffers in the supervisor, by interrupts , and when a return character was received, the control was given to the supervisor, which dumped

1891-473: The default configuration which provides only one. One bank was reserved for the time-sharing supervisory program, the other for user programs. CTSS had a protected-mode kernel; the supervisor's functions in the A-core (memory bank A) could be called only by software interrupts, as in modern operating systems. Causing memory-protection interrupts were used for software interrupts. Processor allocation scheduling with

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1952-559: The design of the Titan Supervisor was inspired by that. Dennis Ritchie wrote in 1977 that UNIX could be seen as a "modern implementation" of CTSS. Multics, which was also developed by Project MAC, was started in the 1960s as a successor to CTSS – and in turn inspired the development of Unix in 1969. One of the technical terms inherited by these systems from CTSS is daemon . Incompatible Timesharing System (ITS), another early, revolutionary, and influential MIT time-sharing system,

2013-399: The dots are assigned in no obvious order, the cells with the fewest dots are assigned to the first three letters (and lowest digits), abc = 123 ( ⠁ ⠃ ⠉ ), and to the three vowels in this part of the alphabet, aei ( ⠁ ⠑ ⠊ ), whereas the even digits 4 , 6 , 8 , 0 ( ⠙ ⠋ ⠓ ⠚ ) are right angles. The next ten letters, k – t , are identical to a – j respectively, apart from

2074-469: The end of 39 letters of the French alphabet to accommodate English. The a – j series shifted down by one dot space ( ⠂ ⠆ ⠒ ⠲ ⠢ ⠖ ⠶ ⠦ ⠔ ⠴ ) is used for punctuation. Letters a ⠁ and c ⠉ , which only use dots in the top row, were shifted two places for the apostrophe and hyphen: ⠄ ⠤ . (These are also the decade diacritics, on the left in the table below, of the second and third decade.) In addition, there are ten patterns that are based on

2135-462: The first two letters ( ⠁ ⠃ ) with their dots shifted to the right; these were assigned to non-French letters ( ì ä ò ⠌ ⠜ ⠬ ), or serve non-letter functions: ⠈ (superscript; in English the accent mark), ⠘ (currency prefix), ⠨ (capital, in English the decimal point ), ⠼ ( number sign ), ⠸ (emphasis mark), ⠐ (symbol prefix). The first four decades are similar in that the numeric sequence

2196-507: The left column and at the top of the right column: that is, the letter ⠍ m . The lines of horizontal braille text are separated by a space, much like visible printed text, so that the dots of one line can be differentiated from the braille text above and below. Different assignments of braille codes (or code pages ) are used to map the character sets of different printed scripts to the six-bit cells. Braille assignments have also been created for mathematical and musical notation. However, because

2257-443: The letters w , x , y , z were reassigned to match English alphabetical order. A convention sometimes seen for letters beyond the basic 26 is to exploit the physical symmetry of braille patterns iconically, for example, by assigning a reversed n to ñ or an inverted s to sh . (See Hungarian Braille and Bharati Braille , which do this to some extent.) A third principle was to assign braille codes according to frequency, with

2318-514: The lower-right dot). Eight-dot braille has the advantages that the casing of each letter is coded in the cell and that every printable ASCII character can be encoded in a single cell. All 256 (2 ) possible combinations of 8 dots are encoded by the Unicode standard. Braille with six dots is frequently stored as Braille ASCII . The first 25 braille letters, up through the first half of the 3rd decade, transcribe a–z (skipping w ). In English Braille,

2379-606: The machine on a time-sharing basis with other programs using the machine simultaneously". In June 1959, Christopher Strachey published a paper "Time Sharing in Large Fast Computers" at the UNESCO Information Processing Conference in Paris, where he envisaged a programmer debugging a program at a console (like a teletype ) connected to the computer, while another program was running in the computer at

2440-424: The mode of the file. Files could also be symbolically linked between directories. A directory listing by listf : Input-output hardware was mostly standard IBM peripherals . These included six data channels connecting to: CTSS was described in a paper presented at the 1962 Spring Joint Computer Conference , and greatly influenced the design of other early time-sharing systems. Maurice Wilkes witnessed CTSS and

2501-408: The need for braille, technological advancements such as braille displays have continued to make braille more accessible and available. Braille users highlight that braille remains as essential as print is to the sighted. ⠏ ⠗ ⠑ ⠍ ⠊ ⠑ ⠗ Braille was based on a tactile code , now known as night writing , developed by Charles Barbier . (The name "night writing" was later given to it when it

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2562-481: The number sign ( ⠼ ) applied to the earlier decades, though that only caught on for the digits (the old 5th decade being replaced by ⠼ applied to the 1st decade). The dash occupying the top row of the original sixth decade was simply omitted, producing the modern fifth decade. (See 1829 braille .) Historically, there have been three principles in assigning the values of a linear script (print) to Braille: Using Louis Braille's original French letter values; reassigning

2623-399: The on-screen braille input keyboard, to type braille symbols on to their device by placing their fingers on to the screen according to the dot configuration of the symbols they wish to form. These symbols are automatically translated into print on the screen. The different tools that exist for writing braille allow the braille user to select the method that is best for a given task. For example,

2684-445: The pattern of the dots.) Third, the code did not include symbols for numerals or punctuation. Braille's solution was to use 6-dot cells and to assign a specific pattern to each letter of the alphabet. Braille also developed symbols for representing numerals and punctuation. At first, braille was a one-to-one transliteration of the French alphabet, but soon various abbreviations (contractions) and even logograms were developed, creating

2745-537: The quotation marks and parentheses (to ⠶ and ⠦ ⠴ ); it uses ( ⠲ ) for both the period and the decimal point, and the English decimal point ( ⠨ ) to mark capitalization. Braille contractions are words and affixes that are shortened so that they take up fewer cells. In English Braille, for example, the word afternoon is written with just three letters, ⠁ ⠋ ⠝ ⟨afn⟩ , much like stenoscript . There are also several abbreviation marks that create what are effectively logograms . The most common of these

2806-609: The race was on to calculate and predict where the first man-made satellites would appear in the sky. Fred Lawrence Whipple , then director of the Smithsonian Astrophysical Observatory (SAO) in Cambridge, Massachusetts, had gathered amateur astronomers to track artificial satellites in an organization called Operation Moonwatch . The aim was to get the position of the satellite in order to obtain its orbital elements . The first "satisfactory orbit" calculated by

2867-417: The rest of that decade is rounded out with the ligatures and, for, of, the, and with . Omitting dot 3 from these forms the 4th decade, the ligatures ch, gh, sh, th, wh, ed, er, ou, ow and the letter w . (See English Braille .) Various formatting marks affect the values of the letters that follow them. They have no direct equivalent in print. The most important in English Braille are: That is, ⠠ ⠁

2928-569: The running code to the tape and decided what to run next. The console commands implemented at the time were login, logout, input, edit, fap, mad, madtrn, load, use, start, skippm, listf, printf, xdump and xundump . This became the initial version of the Compatible Time-Sharing System. This was apparently the first ever public demonstration of time-sharing ; there are other claims, but they refer to special-purpose systems, or with no known papers published. The "compatibility" of CTSS

2989-543: The same time, decided the details of implementing such system at MIT, and started the development of the system. By July, 1961 a few time sharing commands had become operational on the Computation Center's IBM 709, and in November 1961, Fernando J. Corbató demonstrated at MIT what was called the Experimental Time-Sharing System . On May 3, 1962, F. J. Corbató, M. M. Daggett and R. C. Daley published

3050-406: The same time. Debugging programs was an important problem at that time, because with batch processing, it then often took a day from submitting a changed code, to getting the results. John McCarthy wrote a memo about that at MIT, after which a preliminary study committee and a working committee were established at MIT, to develop time sharing. The committees envisaged many users using the computer at

3111-542: The simplest patterns (quickest ones to write with a stylus) assigned to the most frequent letters of the alphabet. Such frequency-based alphabets were used in Germany and the United States in the 19th century (see American Braille ), but with the invention of the braille typewriter their advantage disappeared, and none are attested in modern use – they had the disadvantage that the resulting small number of dots in

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3172-414: The six positions, producing 64 (2 ) possible patterns, including one in which there are no raised dots. For reference purposes, a pattern is commonly described by listing the positions where dots are raised, the positions being universally numbered, from top to bottom, as 1 to 3 on the left and 4 to 6 on the right. For example, dot pattern 1-3-4 describes a cell with three dots raised, at the top and bottom in

3233-415: The six-dot braille cell allows only 64 (2 ) patterns, including space, the characters of a braille script commonly have multiple values, depending on their context. That is, character mapping between print and braille is not one-to-one. For example, the character ⠙ corresponds in print to both the letter d and the digit 4 . In addition to simple encoding, many braille alphabets use contractions to reduce

3294-404: The size of braille texts and to increase reading speed. (See Contracted braille .) Braille may be produced by hand using a slate and stylus in which each dot is created from the back of the page, writing in mirror image, or it may be produced on a braille typewriter or Perkins Brailler , or an electronic Brailler or braille notetaker. Braille users with access to smartphones may also activate

3355-577: Was an experimental, pilot-model machine-oriented bibliographic storage and retrieval system with a database that stored a catalog of roughly 15,000 journal articles. It was used to develop and test concepts for library automation. A deployment of three BRISC CRT consoles for testing at the MIT Engineering Library showed that it was preferred over two other systems, ARDS and DATEL. CTSS used a modified IBM 7090 mainframe computer that had two 32,768 (32K) 36-bit- word banks of core memory instead of

3416-454: Was considered as a means for soldiers to communicate silently at night and without a light source, but Barbier's writings do not use this term and suggest that it was originally designed as a simpler form of writing and for the visually impaired.) In Barbier's system, sets of 12 embossed dots were used to encode 36 different sounds. Braille identified three major defects of the code: first, the symbols represented phonetic sounds and not letters of

3477-403: Was converted to Grade 2 Braille. The following month the feasibility of converting textbook information on teletypesetter tape to error-free Grade 2 Braille was successfully demonstrated. As MIT CTSS was an academic system, a research vehicle and not a system for commercial computing, two years later a version of DOTSYS stripped of CTSS dependencies for software portability was used on an IBM 709 at

3538-749: Was introduced around 1933. In 1951 David Abraham, a woodworking teacher at the Perkins School for the Blind , produced a more advanced Braille typewriter, the Perkins Brailler . Braille printers or embossers were produced in the 1950s. In 1960 Robert Mann, a teacher in MIT, wrote DOTSYS , a software that allowed automatic braille translation , and another group created an embossing device called "M.I.T. Braillemboss". The Mitre Corporation team of Robert Gildea, Jonathan Millen, Reid Gerhart and Joseph Sullivan (now president of Duxbury Systems) developed DOTSYS III,

3599-454: Was produced by people who disagreed with the direction taken by CTSS, and later, Multics; the name was a parody of "CTSS", as later the name "Unix" was a parody of "Multics". CTSS and ITS file systems have a number of design elements in common. Both have an M.F.D. (master file directory) and one or more U.F.D. (user file directories). Neither of them have nested directories (sub-directories). Both have file names consisting of two names which are

3660-744: Was the first binary form of writing developed in the modern era. Braille characters are formed using a combination of six raised dots arranged in a 3 × 2 matrix, called the braille cell. The number and arrangement of these dots distinguishes one character from another. Since the various braille alphabets originated as transcription codes for printed writing, the mappings (sets of character designations) vary from language to language, and even within one; in English braille there are three levels: uncontracted  – a letter-by-letter transcription used for basic literacy; contracted  – an addition of abbreviations and contractions used as

3721-455: Was with background jobs run on the same computer, which generally used more of the compute resources than the time-sharing functions. The first version of the DOTSYS braille translation software ran on CTSS and could output to a BRAILLEMBOSS braille page printer. DOTSYS on CTSS was first demonstrated on August 18, 1966, as part of a feasibility study where teletypesetter tape, in the form of news,

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