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77-631: The watchword of the confederation was: "Fight against Saxony and Russia for political independence of the Polish–Lithuanian Commonwealth and carry out political reforms." They attempted unsuccessfully to gain Czech and Hungarian support, as well as from Silesian citizens. They also dispatched envoys to Sweden, France, the Ottoman Empire, and the Vatican. The confederation was defeated, with

154-410: A cryptographic hash of the password. If an attacker gets access to the file of hashed passwords guessing can be done offline, rapidly testing candidate passwords against the true password's hash value. In the example of a web-server, an online attacker can guess only at the rate at which the server will respond, while an off-line attacker (who gains access to the file) can guess at a rate limited only by

231-400: A log in process that controls access to protected computer operating systems , mobile phones , cable TV decoders, automated teller machines (ATMs), etc. A typical computer user has passwords for many purposes: logging into accounts, retrieving e-mail , accessing applications, databases, networks, web sites, and even reading the morning newspaper online. The easier a password is for

308-467: 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

385-399: A polynomial , modulus , or an advanced hash function . Roger Needham invented the now-common approach of storing only a "hashed" form of the plaintext password. When a user types in a password on such a system, the password handling software runs through a cryptographic hash algorithm, and if the hash value generated from the user's entry matches the hash stored in the password database,

462-400: A challenge because of the sheer number of passwords users of computers and the internet are expected to maintain. One survey concluded that the average user has around 100 passwords. To manage the proliferation of passwords, some users employ the same password for multiple accounts, a dangerous practice since a data breach in one account could compromise the rest. Less risky alternatives include

539-430: A challenge, and answered with the correct response— thunder . The challenge and response were changed every three days. American paratroopers also famously used a device known as a "cricket" on D-Day in place of a password system as a temporarily unique method of identification; one metallic click given by the device in lieu of a password was to be met by two clicks in reply. Passwords have been used with computers since

616-446: 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 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

693-400: A consistent theme to keep their passwords memorable. Because of these issues, there is some debate as to whether password aging is effective. Changing a password will not prevent abuse in most cases, since the abuse would often be immediately noticeable. However, if someone may have had access to the password through some means, such as sharing a computer or breaching a different site, changing

770-496: 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 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

847-484: A few important accounts, such as bank accounts. Similar arguments were made by Forbes in not change passwords as often as many "experts" advise, due to the same limitations in human memory. Historically, many security experts asked people to memorize their passwords: "Never write down a password". More recently, many security experts such as Bruce Schneier recommend that people use passwords that are too complicated to memorize, write them down on paper, and keep them in

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924-410: A good choice of password. They found that passwords based on thinking of a phrase and taking the first letter of each word are just as memorable as naively selected passwords, and just as hard to crack as randomly generated passwords. Combining two or more unrelated words and altering some of the letters to special characters or numbers is another good method, but a single dictionary word is not. Having

1001-537: A larger construction such as in PBKDF2 . The stored data—sometimes called the "password verifier" or the "password hash"—is often stored in Modular Crypt Format or RFC 2307 hash format, sometimes in the /etc/passwd file or the /etc/shadow file. The main storage methods for passwords are plain text, hashed, hashed and salted, and reversibly encrypted. If an attacker gains access to the password file, then if it

1078-662: A match, they know that their guess is the actual password for the associated user. Password cracking tools can operate by brute force (i.e. trying every possible combination of characters) or by hashing every word from a list; large lists of possible passwords in many languages are widely available on the Internet. The existence of password cracking tools allows attackers to easily recover poorly chosen passwords. In particular, attackers can quickly recover passwords that are short, dictionary words, simple variations on dictionary words, or that use easily guessable patterns. A modified version of

1155-569: 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 a separate IBM 7094 that was received in October 1963 (the "red machine") was used early on in Project MAC until 1969 when

1232-613: 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 the same time. Debugging programs was an important problem at that time, because with batch processing, it then often took a day from submitting

1309-483: A password follow. The rate at which an attacker can submit guessed passwords to the system is a key factor in determining system security. Some systems impose a time-out of several seconds after a small number (e.g., three) of failed password entry attempts, also known as throttling. In the absence of other vulnerabilities, such systems can be effectively secure with relatively simple passwords if they have been well chosen and are not easily guessed. Many systems store

1386-459: A password or watchword , and would only allow a person or group to pass if they knew the password. Polybius describes the system for the distribution of watchwords in the Roman military as follows: The way in which they secure the passing round of the watchword for the night is as follows: from the tenth maniple of each class of infantry and cavalry, the maniple which is encamped at the lower end of

1463-416: A personally designed algorithm for generating obscure passwords is another good method. However, asking users to remember a password consisting of a "mix of uppercase and lowercase characters" is similar to asking them to remember a sequence of bits: hard to remember, and only a little bit harder to crack (e.g. only 128 times harder to crack for 7-letter passwords, less if the user simply capitalises one of

1540-491: A precautionary measure. If a new password is passed to the system in unencrypted form, security can be lost (e.g., via wiretapping ) before the new password can even be installed in the password database and if the new password is given to a compromised employee, little is gained. Some websites include the user-selected password in an unencrypted confirmation e-mail message, with the obvious increased vulnerability. Identity management systems are increasingly used to automate

1617-448: 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 the machine on a time-sharing basis with other programs using the machine simultaneously". In June 1959, Christopher Strachey published

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1694-466: A risk of alienating users, possibly decreasing security as a result. It is common practice amongst computer users to reuse the same password on multiple sites. This presents a substantial security risk, because an attacker needs to only compromise a single site in order to gain access to other sites the victim uses. This problem is exacerbated by also reusing usernames , and by websites requiring email logins, as it makes it easier for an attacker to track

1771-579: A single user across multiple sites. Password reuse can be avoided or minimized by using mnemonic techniques , writing passwords down on paper , or using a password manager . It has been argued by Redmond researchers Dinei Florencio and Cormac Herley, together with Paul C. van Oorschot of Carleton University, Canada, that password reuse is inevitable, and that users should reuse passwords for low-security websites (which contain little personal data and no financial information, for example) and instead focus their efforts on remembering long, complex passwords for

1848-572: A system of storing login passwords in a hashed form as part of the Unix operating system. The system was based on a simulated Hagelin rotor crypto machine, and first appeared in 6th Edition Unix in 1974. A later version of his algorithm, known as crypt(3) , used a 12-bit salt and invoked a modified form of the DES algorithm 25 times to reduce the risk of pre-computed dictionary attacks . In modern times, user names and passwords are commonly used by people during

1925-510: A typical individual accesses can make memorization of unique passwords for each service impractical. Using the terminology of the NIST Digital Identity Guidelines, the secret is held by a party called the claimant while the party verifying the identity of the claimant is called the verifier . When the claimant successfully demonstrates knowledge of the password to the verifier through an established authentication protocol ,

2002-409: 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

2079-442: A wallet. Password manager software can also store passwords relatively safely, in an encrypted file sealed with a single master password. To facilitate estate administration, it is helpful for people to provide a mechanism for their passwords to be communicated to the persons who will administer their affairs in the event of their death. Should a record of accounts and passwords be prepared, care must be taken to ensure that

2156-472: Is a feature of some operating systems which forces users to change passwords frequently (e.g., quarterly, monthly or even more often). Such policies usually provoke user protest and foot-dragging at best and hostility at worst. There is often an increase in the number of people who note down the password and leave it where it can easily be found, as well as help desk calls to reset a forgotten password. Users may use simpler passwords or develop variation patterns on

2233-413: Is cracking both necessary and possible. If a cryptographic hash function is well designed, it is computationally infeasible to reverse the function to recover a plaintext password. An attacker can, however, use widely available tools to attempt to guess the passwords. These tools work by hashing possible passwords and comparing the result of each guess to the actual password hashes. If the attacker finds

2310-431: Is made, possibly supplying a code that must be entered in addition to a password. More sophisticated factors include such things as hardware tokens and biometric security. Password rotation is a policy that is commonly implemented with the goal of enhancing computer security . In 2019, Microsoft stated that the practice is "ancient and obsolete". Most organizations specify a password policy that sets requirements for

2387-612: Is sometimes used to distribute passwords but this is generally an insecure method. Since most email is sent as plaintext , a message containing a password is readable without effort during transport by any eavesdropper. Further, the message will be stored as plaintext on at least two computers: the sender's and the recipient's. If it passes through intermediate systems during its travels, it will probably be stored on there as well, at least for some time, and may be copied to backup , cache or history files on any of these systems. Using client-side encryption will only protect transmission from

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2464-450: Is stored as plain text, no cracking is necessary. If it is hashed but not salted then it is vulnerable to rainbow table attacks (which are more efficient than cracking). If it is reversibly encrypted then if the attacker gets the decryption key along with the file no cracking is necessary, while if he fails to get the key cracking is not possible. Thus, of the common storage formats for passwords only when passwords have been salted and hashed

2541-481: Is the Transport Layer Security (TLS, previously called SSL ) feature built into most current Internet browsers . Most browsers alert the user of a TLS/SSL-protected exchange with a server by displaying a closed lock icon, or some other sign, when TLS is in use. There are several other techniques in use. There is a conflict between stored hashed-passwords and hash-based challenge–response authentication ;

2618-601: Is to prevent bystanders from reading the password; however, some argue that this practice may lead to mistakes and stress, encouraging users to choose weak passwords. As an alternative, users should have the option to show or hide passwords as they type them. Effective access control provisions may force extreme measures on criminals seeking to acquire a password or biometric token. Less extreme measures include extortion , rubber hose cryptanalysis , and side channel attack . Some specific password management issues that must be considered when thinking about, choosing, and handling,

2695-499: The DES algorithm was used as the basis for the password hashing algorithm in early Unix systems. The crypt algorithm used a 12-bit salt value so that each user's hash was unique and iterated the DES algorithm 25 times in order to make the hash function slower, both measures intended to frustrate automated guessing attacks. The user's password was used as a key to encrypt a fixed value. More recent Unix or Unix-like systems (e.g., Linux or

2772-507: 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 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

2849-667: 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 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

2926-457: 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, was converted to Grade 2 Braille. The following month the feasibility of converting textbook information on teletypesetter tape to error-free Grade 2 Braille

3003-431: The attacker. Some systems, such as PGP and Wi-Fi WPA , apply a computation-intensive hash to the password to slow such attacks, in a technique known as key stretching . An alternative to limiting the rate at which an attacker can make guesses on a password is to limit the total number of guesses that can be made. The password can be disabled, requiring a reset, after a small number of consecutive bad guesses (say 5); and

3080-436: The authenticating machine or person. If the password is carried as electrical signals on unsecured physical wiring between the user access point and the central system controlling the password database, it is subject to snooping by wiretapping methods. If it is carried as packeted data over the Internet, anyone able to watch the packets containing the logon information can snoop with a very low probability of detection. Email

3157-508: The composition and usage of passwords, typically dictating minimum length, required categories (e.g., upper and lower case, numbers, and special characters), prohibited elements (e.g., use of one's own name, date of birth, address, telephone number). Some governments have national authentication frameworks that define requirements for user authentication to government services, including requirements for passwords. Compatible Time-Sharing System The Compatible Time-Sharing System ( CTSS )

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3234-418: The conflict and limitation of hash-based methods. An augmented system allows a client to prove knowledge of the password to a server, where the server knows only a (not exactly) hashed password, and where the un-hashed password is required to gain access. Usually, a system must provide a way to change a password, either because a user believes the current password has been (or might have been) compromised, or as

3311-562: 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,

3388-430: The dictionary sense) may be harder to guess, which is a desirable property of passwords. A memorized secret consisting of a sequence of words or other text separated by spaces is sometimes called a passphrase . A passphrase is similar to a password in usage, but the former is generally longer for added security. Passwords have been used since ancient times. Sentries would challenge those wishing to enter an area to supply

3465-429: The earliest days of computing. The Compatible Time-Sharing System (CTSS), an operating system introduced at MIT in 1961, was the first computer system to implement password login. CTSS had a LOGIN command that requested a user password. "After typing PASSWORD, the system turns off the printing mechanism, if possible, so that the user may type in his password with privacy." In the early 1970s, Robert Morris developed

3542-524: The hardware on which the attack is running and the strength of the algorithm used to create the hash. Passwords that are used to generate cryptographic keys (e.g., for disk encryption or Wi-Fi security) can also be subjected to high rate guessing, known as password cracking . Lists of common passwords are widely available and can make password attacks very efficient. Security in such situations depends on using passwords or passphrases of adequate complexity, making such an attack computationally infeasible for

3619-510: The hash is used as a shared secret, an attacker does not need the original password to authenticate remotely; they only need the hash. Rather than transmitting a password, or transmitting the hash of the password, password-authenticated key agreement systems can perform a zero-knowledge password proof , which proves knowledge of the password without exposing it. Moving a step further, augmented systems for password-authenticated key agreement (e.g., AMP , B-SPEKE , PAK-Z , SRP-6 ) avoid both

3696-494: 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 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

3773-492: The issuance of replacements for lost passwords, a feature called self-service password reset . The user's identity is verified by asking questions and comparing the answers to ones previously stored (i.e., when the account was opened). Some password reset questions ask for personal information that could be found on social media, such as mother's maiden name. As a result, some security experts recommend either making up one's own questions or giving false answers. "Password aging"

3850-450: The last armed struggles taking place in 1736 near Kurpie and Podolia. This Polish history –related article is a stub . You can help Misplaced Pages by expanding it . Watchword A password , sometimes called a passcode , is secret data, typically a string of characters, usually used to confirm a user's identity. Traditionally, passwords were expected to be memorized , but the large number of password-protected services that

3927-427: The latter requires a client to prove to a server that they know what the shared secret (i.e., password) is, and to do this, the server must be able to obtain the shared secret from its stored form. On many systems (including Unix -type systems) doing remote authentication, the shared secret usually becomes the hashed form and has the serious limitation of exposing passwords to offline guessing attacks. In addition, when

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4004-580: The letters). Asking users to use "both letters and digits" will often lead to easy-to-guess substitutions such as 'E' → '3' and 'I' → '1', substitutions that are well known to attackers. Similarly typing the password one keyboard row higher is a common trick known to attackers. In 2013, Google released a list of the most common password types, all of which are considered insecure because they are too easy to guess (especially after researching an individual on social media), which includes: Traditional advice to memorize passwords and never write them down has become

4081-459: The like. Physical security issues are also a concern, from deterring shoulder surfing to more sophisticated physical threats such as video cameras and keyboard sniffers. Passwords should be chosen so that they are hard for an attacker to guess and hard for an attacker to discover using any of the available automatic attack schemes. Nowadays, it is a common practice for computer systems to hide passwords as they are typed. The purpose of this measure

4158-421: The mail handling system server to the client machine. Previous or subsequent relays of the email will not be protected and the email will probably be stored on multiple computers, certainly on the originating and receiving computers, most often in clear text. The risk of interception of passwords sent over the Internet can be reduced by, among other approaches, using cryptographic protection. The most widely used

4235-448: The marks from what quarter the tablet has not returned, and whoever is responsible for the stoppage meets with the punishment he merits. Passwords in military use evolved to include not just a password, but a password and a counterpassword; for example in the opening days of the Battle of Normandy , paratroopers of the U.S. 101st Airborne Division used a password— flash —which was presented as

4312-424: 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

4389-416: The owner to remember generally means it will be easier for an attacker to guess. However, passwords that are difficult to remember may also reduce the security of a system because (a) users might need to write down or electronically store the password, (b) users will need frequent password resets and (c) users are more likely to re-use the same password across different accounts. Similarly, the more stringent

4466-466: The password limits the window for abuse. Allotting separate passwords to each user of a system is preferable to having a single password shared by legitimate users of the system, certainly from a security viewpoint. This is partly because users are more willing to tell another person (who may not be authorized) a shared password than one exclusively for their use. Single passwords are also much less convenient to change because many people need to be told at

4543-428: The password requirements, such as "have a mix of uppercase and lowercase letters and digits" or "change it monthly", the greater the degree to which users will subvert the system. Others argue longer passwords provide more security (e.g., entropy ) than shorter passwords with a wide variety of characters. In The Memorability and Security of Passwords , Jeff Yan et al. examine the effect of advice given to users about

4620-399: The records are secure, to prevent theft or fraud. Multi-factor authentication schemes combine passwords (as "knowledge factors") with one or more other means of authentication, to make authentication more secure and less vulnerable to compromised passwords. For example, a simple two-factor login might send a text message, e-mail, automated phone call, or similar alert whenever a login attempt

4697-628: 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 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

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4774-420: The same password for accounts on different systems, those will be compromised as well. More secure systems store each password in a cryptographically protected form, so access to the actual password will still be difficult for a snooper who gains internal access to the system, while validation of user access attempts remains possible. The most secure do not store passwords at all, but a one-way derivation, such as

4851-401: The same time, and they make removal of a particular user's access more difficult, as for instance on graduation or resignation. Separate logins are also often used for accountability, for example to know who changed a piece of data. Common techniques used to improve the security of computer systems protected by a password include: Some of the more stringent policy enforcement measures can pose

4928-406: The same until it reaches the first maniples, those encamped near the tents of the tribunes. These latter are obliged to deliver the tablet to the tribunes before dark. So that if all those issued are returned, the tribune knows that the watchword has been given to all the maniples, and has passed through all on its way back to him. If any one of them is missing, he makes inquiry at once, as he knows by

5005-411: The street, a man is chosen who is relieved from guard duty, and he attends every day at sunset at the tent of the tribune , and receiving from him the watchword—that is a wooden tablet with the word inscribed on it – takes his leave, and on returning to his quarters passes on the watchword and tablet before witnesses to the commander of the next maniple, who in turn passes it to the one next to him. All do

5082-457: 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 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

5159-473: The use of password managers , single sign-on systems and simply keeping paper lists of less critical passwords. Such practices can reduce the number of passwords that must be memorized, such as the password manager's master password, to a more manageable number. The security of a password-protected system depends on several factors. The overall system must be designed for sound security, with protection against computer viruses , man-in-the-middle attacks and

5236-519: The user is permitted access. The hash value is created by applying a cryptographic hash function to a string consisting of the submitted password and, in many implementations, another value known as a salt . A salt prevents attackers from easily building a list of hash values for common passwords and prevents password cracking efforts from scaling across all users. MD5 and SHA1 are frequently used cryptographic hash functions, but they are not recommended for password hashing unless they are used as part of

5313-408: The user may be required to change the password after a larger cumulative number of bad guesses (say 30), to prevent an attacker from making an arbitrarily large number of bad guesses by interspersing them between good guesses made by the legitimate password owner. Attackers may conversely use knowledge of this mitigation to implement a denial of service attack against the user by intentionally locking

5390-421: The user out of their own device; this denial of service may open other avenues for the attacker to manipulate the situation to their advantage via social engineering . Some computer systems store user passwords as plaintext , against which to compare user logon attempts. If an attacker gains access to such an internal password store, all passwords—and so all user accounts—will be compromised. If some users employ

5467-422: The various BSD systems) use more secure password hashing algorithms such as PBKDF2 , bcrypt , and scrypt , which have large salts and an adjustable cost or number of iterations. A poorly designed hash function can make attacks feasible even if a strong password is chosen. LM hash is a widely deployed and insecure example. Passwords are vulnerable to interception (i.e., "snooping") while being transmitted to

5544-403: The verifier is able to infer the claimant's identity. In general, a password is an arbitrary string of characters including letters, digits, or other symbols. If the permissible characters are constrained to be numeric, the corresponding secret is sometimes called a personal identification number (PIN). Despite its name, a password does not need to be an actual word; indeed, a non-word (in

5621-455: 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

5698-460: 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 a quantum time unit 200 ms, was controlled by

5775-560: 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 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,

5852-468: Was the first general purpose time-sharing operating system . Compatible Time Sharing referred to time sharing which was compatible with batch processing ; it could offer both time sharing and batch processing concurrently. 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

5929-474: 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 the default configuration which provides only one. One bank

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