Topic: uniform representation of files and sequences

topics > computer science > data > Group: sequences

file input/output
I/O streams
processing a sequence
uniform data model
uniform language systems
software tools
Unix pipes


Uniform representation of sequences, especially input/output files, encourages the development of software tools. File i/o is the simplest example, with all external data as sequences of bytes despite their physical implementation as disk sectors and tape records. Consistent link and load format representations allow incremental linking and program execution. Software tools as defined by Kernighan and Plauger use text files for consistent input and output. This allows several programs to be chained together. Multiple pass programs should produce consistent intermediate files to allow for latter addition or deletion of program passes. (cbb 5/80)
Subtopic: filter programs up

Quote: pipes with filters require a uniform data format [»kernBW_1975, OK]
Quote: in Unix a file is a sequence of bytes no matter what device it resides on [»kernBW1_1979]
Quote: expect the output of every program to become the input of other programs; avoid rigid formats, extraneous information, and interactive inputs [»mcilMD7_1978]

Subtopic: memory as bytes up

Quote: IBM 360 generalized machine memory as a sequence of bytes with uniform addressing independent of type [»dehnJC4_1998]

Subtopic: resources as file up

Quote: the 8 1/2 windowing system treats all resources as multiplexed files; e.g., /dev/bitblt; X window functionality in 10,000 lines of code [»pikeR6_1991]

Subtopic: directory as file up

Quote: by making directories normal files, directory programs are outside of the system [»kernBW1_1979]

Subtopic: well-known name up

Quote: Plan 9 uses the same name for different files/services in different processes; fundamental to system [»pikeR6_2000]

Subtopic: file as sequence up

Quote: a file is an ordered sequence of elements without format; all formatting by higher-level modules or programs [»daleRC_1965]
Quote: a file is a linear array of data accessed by name or by segment number plus offset; independent of device
Quote: file system implemented in Multics [»daleRC_1965]

Subtopic: uniform intermediate representation up

Quote: in multi-pass programs with different intermediate formats, can not remove a pass [»parnDL5_1978]

Subtopic: strings for conversion up

Quote: SUIT uses string conversion to save data types and to convert between types [»pausR10_1992, OK]
Quote: character strings are important for communicating between modules of a large system [»boehHJ12_1995]
Quote: desired properties for strings: immutable strings, long strings, files as strings, efficient non-destructive concatenation and substring operations

Related Topics up

Topic: file (22 items)
Topic: file input/output (21 items)
Topic: I/O streams (17 items)
Topic: processing a sequence (17 items)
Topic: uniform data model (19 items)
Topic: uniform language systems (25 items)
Topic: software tools (20 items)
Topic: Unix pipes
(10 items)

Updated barberCB 3/05
Copyright © 2002-2008 by C. Bradford Barber. All rights reserved.
Thesa is a trademark of C. Bradford Barber.