Browse Prior Art Database

Network UNIX (RFC0681)

IP.com Disclosure Number: IPCOM000003730D
Original Publication Date: 1975-Mar-01
Included in the Prior Art Database: 2019-Feb-14
Document File: 8 page(s) / 12K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

S. Holmgren: AUTHOR

Related Documents

10.17487/RFC0681: DOI

Abstract

Capabilities as an ARPANET Mini-Host: standard I/O, Telnet, NCP, Hardware/Software requirements, reliability, availability.

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NWG/RFC# 681 JBP 14-MAY-75 14:38 32157 3/18/75 NETWORK UNIX S. Holmgren

NETWORK UNIX 1

RFC 681 NIC 32157 2

INTRODUCTION 3

THE UNIX TIME-SHARING SYSTEM [1] PRESENTS SEVERAL INTERESTING CAPABILITIES AS AN ARPA NETWORK MINI-HOST. IT OFFERS POWERFUL LOCAL PROCESSING FACILITIES IN TERMS OF USER PROGRAMS, SEVERAL COMPILERS, AN EDITOR BASED ON QED, A VERSATILE DOCUMENT PREPARATION SYSTEM, AND AN EFFICIENT FILE SYSTEM FEATURING SOPHISTICATED ACCESS CONTROL, MOUNTABLE AND DE-MOUNTABLE VOLUMES, AND A UNIFIED TREATMENT OF PERIPHERALS AS SPECIAL FILES. 3a

THE NETWORK CONTROL PROGRAM (NCP), IS INTEGRATED WITHIN THE UNIX FILE SYSTEM. NETWORK CONNECTIONS ARE TREATED AS SPECIAL FILES WHICH CAN BE ACCESSED THROUGH STANDARD UNIX I/O CALLS; VIZ. READ, WRITE, OPEN, CLOSE. SPECIAL FILES HAVE DIRECTORY ENTRIES SIMILAR TO NORMAL FILES EXCEPT THAT CERTAIN FLAG BITS ARE SET. THESE FLAG BITS CAUSE SYSTEM I/O ROUTINES TO TAKE SPECIAL ACTION. IN UNIX, SPECIAL FILES SIGNIFY PERIPHERAL DEVICES. FOR EXAMPLE, I/O TRANSACTION WITH MAGTAPE ZERO WOULD BE ACCOMPLISHED BY ACCESSING THE SPECIAL FILE, "/DEV/MT0". FOR THE UNIX NETWORK SYSTEM, ADDITIONAL SPECIAL FILES WERE CREATED EACH OF WHICH SPECIFIES A HOST ON THE ARPA NETWORK. FOR EXAMPLE "/DEV/NET/HARV" REPRESENTS THE PDP-10 AT HARVARD. THIS SIMPLE ACCESS MECHANISM, THROUGH THE FILING SYSTEM, ALLOWS STANDARD ARPA PROTOCOLS SUCH AS TELNET AND FTP TO BE IMPLEMENTED AS SWAPPABLE USER PROGRAMS, RESIDENT ONLY WHEN NEEDED. FURTHERMORE, A USER MAY WRITE HIS OWN PROGRAMS TO COMMUNICATE WITH THESE SPECIAL FILES JUST AS THE TELNET PROGRAM DOES. THE SAMPLE PROGRAM FOUND BELOW DEPICTS THE ESSENTIALS OF NETWORKING FROM UNIX. 3b

STANDARD I/O 4

TO PRESENT THE BASIC PROPERTIES OF UNIX I/O, THE READ, WRITE, OPEN, AND CLOSE FUNCTION CALLS ARE SUMMARIZED BELOW. EACH CALL MAY RESULT IN AN ERROR CODE OF MINUS ONE. 4a

TO MANIPULATE AN EXISTING FILE WITH READS OR WRITES, IT MUST FIRST BE OPENED WITH THE FOLLOWING CALL: 4b

NWG/RFC# 681 JBP 14-MAY-75 14:38 32157 3/18/75 NETWORK UNIX S. Holmgren

FILEDES = OPEN( "ANYFILENAME",FLAG ) 4b1

WHERE "ANYFILENAME" IS THE ARBITRARY NAME OF THE FILE TO BE OPENED. THE SECOND PARAMETER INDICATES WHETHER THE FILE IS TO BE READ, WRITTEN, OR UPDATED. THE RETURNED VALUE "FILEDES", IS CALLED A FILE DESCRIPTOR. IT IS AN INTEGER USED TO IDENTIFY THE FILE IN SUBSEQUENT CALLS TO READ AND WRITE. 4c

ONCE A FILE HAS BEEN OPENED, THE FOLLOWING CALLS MAY BE USED: 4d

NBYTES = READ( FILEDES,BUFFER,COUNT ); NBYTES = WRITE( FILEDES,BUFFER,COUNT ); 4d1

COUNT IS THE NUMBER OF BYTES TO BE TRANSMITTED BETWEEN THE FILE REPRESENTED BY ’FILEDES’ AND THE BYTE ARRAY REPRESENTED BY ’BUFFER’. NBYTES IS THE NUMBER ACTUALLY TRANSMITTED. FOR THE READ CALL, ’NBYTES’ MAY BE ZERO TO INDICATE THE END OF FILE; IN EITHER CASE, MINUS ONE WILL BE RETURNED IF THERE WAS AN ERROR. 4e

FOR EACH OPEN FILE, THE SYSTEM MAINTAINS A POINTER TO THE NEXT BYTE TO BE READ OR WRITTEN. IF N BYTES ARE TRANSMITTED, THE POINTER ADVANCES N BYTES. DATA WRITTEN TO A FILE AFFE...

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