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cdc_6500_survival_guide [2021/03/15 23:16] – [File System] hc9cdc_6500_survival_guide [2022/12/05 06:33] (current) hc9
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 ====== CDC 6500 Survival Guide ====== ====== CDC 6500 Survival Guide ======
  
-The [[https://en.wikipedia.org/wiki/CDC_6000_series|CDC 6000 series]] was a family of mainframe computers designed by Seymour Cray and James E. Thornton and manufactured by Control Data Corporation in the 1960s. The computers in the series were extremely fast for their time and considered to be the first supercomputers.+The [[wp>CDC_6000_series|CDC 6000 series]] was a family of mainframe computers designed by Seymour Cray and James E. Thornton and manufactured by Control Data Corporation in the 1960s. The computers in the series were extremely fast for their time and considered to be the first supercomputers.
  
 The [[http://www.livingcomputermuseum.org/|Living Computer Museum]] has recently refurbished and put on-line a [[http://www.livingcomputermuseum.org/The-Collection/Exhibit-Hall.aspx#Mainframe|CDC 6500 supercomputer]]. The system was originally used at Purdue University from 1967 to 1989. The [[http://www.livingcomputermuseum.org/|Living Computer Museum]] has recently refurbished and put on-line a [[http://www.livingcomputermuseum.org/The-Collection/Exhibit-Hall.aspx#Mainframe|CDC 6500 supercomputer]]. The system was originally used at Purdue University from 1967 to 1989.
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 A basic understanding of the 6500 file system is necessary to use most IAF comands. A basic understanding of the 6500 file system is necessary to use most IAF comands.
  
-  * **Permanent files** Permanent files are preserved by the system from their creation until their deletion by user command. Each permanent file is owned by a single user and is normally accessible only by its owner, though it is possible to make files accessible by other users as well.+  * **Permanent files*
 +    * Permanent files are preserved by the system from their creation until their deletion by user command. Each permanent file is owned by a single user and is normally accessible only by its owner, though it is possible to make files accessible by other users as well
 +    * Two types of files are supported: 
 +      * **Direct access**  
 +        * Used for random access and database applications. 
 +      * **Indirect access**  
 +        * Common sequential access files, including program source files.
  
-  * Two types of files are supported:+  * **Temporary files** 
 +      * Whenever an indirect access file is accessed, or a new indirect access file created, the system first makes a temporary copy of the file, to which are directed all references and updates to the file. The temporary file must be saved in order for changes to be applied to the permanent file. Unsaved changes will be discarded at the end of the user's session. 
 +      * A temporary file is //not// created when a //direct access// file is opened. Changes made to a direct access file are immediately applied to the permanent file.
  
-    * **Direct access** Used for random access and database applications.+  * **Primary file** 
 +    * The primary file is the temporary file, usually a program source file, that a user is viewing, modifying, or executing at a given time. Although a user session may simultaneously open multiple temporary files, a given user may have only one primary file at a time. 
 +    * The currently selected primary file automatically determines the user's active subsystem. When a new indirect access file is saved as a permanent file for the first time, the file system records the active subsystem at the time. Then when the file is selected as primary sometime later, the system automatically activates the original subsystem.
  
-    * **Indirect access** Common sequential access files, including program source files. +  * **Local files** 
- +    * Local files are the set of temporary files and direct access files (permanent files) currently open by a particular job or user session.
-  * **Temporary files** Whenever an indirect access file is accessed, or a new indirect access file created, the system first makes a temporary copy of the file, to which are directed all references and updates to the file. The temporary file must be saved in order for changes to be applied to the permanent file. Unsaved changes will be discarded at the end of the user's session. +
- +
-  * A temporary file is //not// created when a //direct access// file is opened. Changes made to a direct access file are immediately applied to the permanent file. +
- +
-  * **Primary file** The primary file is the temporary file, usually a program source file, that a user is viewing, modifying, or executing at a given time. Although a user session may simultaneously open multiple temporary files, a given user may have only one primary file at a time. +
- +
-  * The currently selected primary file automatically determines the user's active subsystem. When a new indirect access file is saved as a permanent file for the first time, the file system records the active subsystem at the time. Then when the file is selected as primary sometime later, the system automatically activates the original subsystem. +
- +
-  * **Local files** Local files are the set of temporary files and direct access files (permanent files) currently open by a particular job or user session.+
  
 File names my be up to seven alphanumeric (upper-case) characters and may not begin with a numeric character. The following file names are reserved by the system: File names my be up to seven alphanumeric (upper-case) characters and may not begin with a numeric character. The following file names are reserved by the system:
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 Each programming subsystem includes a simple editing function for entering and modifying program source code in the primary file as follows: Each programming subsystem includes a simple editing function for entering and modifying program source code in the primary file as follows:
  
-To add a source code line:Type a new line sequence number followed by a space and then a program statement. Source code lines will be stored and compiled/executed in the order of line sequence numbers, so lines can be entered in any order.To modify a source code line:Type line sequence number of the program statement to be changed followed by a space and the modified program statement.To delete a source code line:Type the line sequence number followed immediately by the ''Enter'' key.+|To add a source code line:
 +|Type a new line sequence number followed by a space and then a program statement. Source code lines will be stored and compiled/executed in the order of line sequence numbers, so lines can be entered in any order.
 + 
 +|To modify a source code line:
 +|Type line sequence number of the program statement to be changed followed by a space and the modified program statement.
 + 
 +|To delete a source code line:
 +|Type the line sequence number followed immediately by the ''Enter'' key.|
  
   * In the BASIC subsystem, use line sequence numbers as the targets of ''GOTO'' and other statements.   * In the BASIC subsystem, use line sequence numbers as the targets of ''GOTO'' and other statements.
cdc_6500_survival_guide.1615850166.txt.gz · Last modified: 2021/03/15 23:16 by hc9