 music |
 | OSdata.com |
stream input
summary
This subchapter looks at simpe input.
free computer programming text book projecttable of contents
|
stub section
This subchapter is a stub section. It will be filled in with instructional material later. For now it serves the purpose of a place holder for the order of instruction.
Professors are invited to give feedback on both the proposed contents and the propsed order of this text book. Send commentary to Milo, PO Box 1361, Tustin, California, 92781, USA.
stream input
This subchapter looks at stream input.
Pascal eof(x) — Pascal standard function that returns true if the end of file or end of data has been reached; otherwise returns false.
Pascal eoln(x) — Pascal standard function that returns true if the end of line has been reached; otherwise returns false.
BASIC POS(x) — BASIC library function that returns the current position of the video terminal’s cursor..
ALGOL
ALGOL has several common input procedures that allow the input of a character representation (such as from punched cards or teletype machines) of the major ALGOL data types.
The basic form is as follows:
inreal (input device, real varaible name);
The input device is an integer, which represents the inpput device or channel.
The real variable name is the name of a variable of real type that will receive the input.
The procedure starts reading from the designated input device until it finds a sequence of characters that form a valid real value. This character data is automtically translated into the internal real format and stored inthe designated variable.
A related procedure is called ininteger and has similar characteristics as inreal, except that it searches for a valid integer (in character representation) in the input stream and stores the translated integer into a variable with type integer.
ininteger (input device, integer varaible name);
Ada
“42/2 The predefined environment of the language provides for input-output and other capabilities by means of standard library packages. Input-output is supported for values of user-defined as well as of predefined types. Standard means of representing values in display form are also provided.” —:Ada-Europe’s Ada Reference Manual: Introduction: Language Summary See legal information
“2 Finally, a predefined environment of standard packages is provided, including facilities for, among others, input-output, string manipulation, numeric elementary functions, and random number generation.” —:Ada-Europe’s Ada Reference Manual: Section 1: General See legal information
assembly language instructions
Input/Output (I/O) instructions are used to input data from peripherals, output data to peripherals, or read/write input/output controls. Early computers used special hardware to handle I/O devices. The trend in modern computers is to map I/O devices in memory, allowing the direct use of any instruction that operates on memory for handling I/O.
- IN Input; MIX; initiate transfer of information from the input device specified into consecutive locations starting with M, block size implied by unit
- IOC Input-Output Control; MIX; initiate I/O control operation to be performed by designated device
- JRED Jump Ready; MIX; Jump if specified unit is ready (completed previous IN, OUT, or IOC operation); if jump occurs, J-register loaded with the address of the instruction which would have been next if the jump had not been taken
- JBUS Jump Busy; MIX; Jump if specified unit is not ready (not yet completed previous IN, OUT, or IOC operation); if jump occurs, J-register loaded with the address of the instruction which would have been next if the jump had not been taken
MIX devices
Information on the devices for the hypothetical MIX processor’s input/output instructions.
| unit number | peripheral | block size | control |
|---|---|---|---|
| t | Tape unit no. i (0  i 7) | 100 words | M=0, tape rewound; M < 0, skip back M records; M > 0, skip forward M records |
| d | Disk or drum unit no. d (8 d 15) | 100 words | position device according to X-register (extension) |
| 16 | Card reader | 16 words | |
| 17 | Card punch | 16 words | |
| 18 | Printer | 24 words | IOC 0(18) skips printer to top of following page |
| 19 | Typewriter and paper tape | 14 words | paper tape reader: rewind tape |
See also Input/Output Instructions in Assembly Language
There is a temporary stoppage in work on this project because the author is once again homeless. This is a very worthy project that can benefit tens of millions of poor students at a very low cost (hundreds of dollars a month) and a banner ad for the sponsor could lead to millions of dollars of income. If a business is interested in supporting this project, please see project for details.
computers using 
and served using 
.
