1979 5.06 1981

Vol.5 n°6 (#46) june 1980 - On The Subject Of Networking

Vol.5 n°6 (#46) june 1980 - On The Subject Of Networking

(ddj_1980_06_07.jpg)

p.6 A Survey of Computer Networks (p.226 in reprint volume 5)

p.6 A Survey of Computer Networks (p.226 in reprint volume 5)

[author : Art Kleiner] #Networks #Overview

Extract : «  QUBE [...] VIEWDATA [...] PCNET (Personal Computer NETwork) [...] THE SOURCE [...] MICRONET [...] EIES (Electronic Information Exchange System) [...] I. P. Sharp [...] Confer [...] Comet [...] Planet/Notepad [...] PLATO [...] PANALOG [...] American Telephone and Telegraph [...] General Telephone and Electronics [...] Xerox [...] Satellite Business Systems [...] Exxon [...] Datacast [...] Xanadu [...] The Community Memory Project [...] OCLC/Home Delivery of Library Services [...] AIM [...]  »

p.10 The Personal Computer Network (PCNET) Project (p.230 in reprint volume 5)

p.10 The Personal Computer Network (PCNET) Project (p.230 in reprint volume 5)

[author : Dave Caulkins] #Networks

Extract : «  INTRODUCTION

This article describes the PCNET project, its goals, a brief history of activity, PCNET status today, and PCNET’s future plans.

GOALS

The goal of the PCNET project is to provide a reliable, error free and lowcost means of transferring files, programs or messages among personal computers (PCs) via the dial-up telephone system or other media. To achieve this goal in a reasonable way the PCNET Project adopted a series of system design objectives: [...]  »

p.16 MCALL-C: A Communications Protocol for Personal Computers (p.234 in reprint volume 5)

p.16 MCALL-C: A Communications Protocol for Personal Computers (p.234 in reprint volume 5)

[author : Tim J. Pugh, Jr.] #Networks #Protocol #Listing #Assembly

Extract : «  In the protocol description which follows, I will identify alternative approaches that were considered in arriving at the present protocol. But before getting into the protocol itself I would like to try to clear up a misunderstanding that may exist concerning telecommunications protocols. The type of protocol which I am describing has no bearing on the information content of the data. The protocol acts simply as an envelope or container of data. The data is inserted into the envelope at the originating (transmitting) end and automatically removed at the receiving end. Thus, by the time the data is placed on disk, it looks exactly the same as it did on the disk of the originator.

Perhaps the first question to answer is “why have a protocol?” The principal reason for having one is to insure, as far as possible, that no data is lost or garbled in the transmission. One can, and I often do, transmit and/or receive data files with a large Time Sharing Computer (TSC). These TSCs are typically very uncooperative beasts which output the data to you in “their own good time,” usually as fast as it can be sent. They are not concerned about whether you had noise on the line or whether you had time to write the last record to disk. That’s your problem. Thus, if you have a system which pays rapt attention to the incoming data and if the weather is good and you have a high quality modem, then you have an excellent chance of receiving error-free data.

However, one cannot depend on all the above stated conditions being met, especially when two personal computers are involved. Such a transfer will frequently be “long distance.” Each additional TELCO switching center involved in the “call” reduces the signal-to-noise ratio and often there is line “echo” distortion present. Thus, reliable data transfer becomes questionable without an intervening mechanism. An appropriate communications protocol supplies this mechanism. [...]  »

p.21 Electric Phone Book (p.239 in reprint volume 5)

p.21 Electric Phone Book (p.239 in reprint volume 5)

#Networks

A Directory of 144 Computerized Bulletin Board Systems

Extract : «  A computerized bulletin board works just like an ordinary bulletin board system except that instead of paper and thumbtacks it uses a terminal, a computer, and the dial-up telephone network. It’s a place to leave messages for everyone or for some particular person who, you know, browses the bulletin board occasionally. [...]  »

p.22 On Modems (p.240 in reprint volume 5)

p.22 On Modems (p.240 in reprint volume 5)

[author : William Smith] #Networks #Glossary #Initiation

Extract : «  Like all new areas that emerge in this world of microcomputers, the area of phone line connection is fraught with unclear terminology and generalities. I spent much energy sorting things out in order to set myself up ‘on line’ and would like to share some of what I have learned with you. To begin, some terms must be defined:

MODEM a general term that can refer to any of several different aspects of the physical device which couples a computer to the phone lines.

ACOUSTIC COUPLER [...]  »

p.25 Adding Arrays to FORTH (p.242 in reprint volume 5)

p.25 Adding Arrays to FORTH (p.242 in reprint volume 5)

[author : Ralph Deane] #Listing #Forth #Programming

Extract : «  In some versions of FORTH (notably FIGFORTH) there are no functions which can be used to define multidimensioned arrays. Other versions (those based on the Caltech manual) provide only a primitive array defining function. The power of FORTH is such, however, that these array-defining functions can be added with relative ease. This extendability of the compiler to add new classes of functions (in this case arrays) is shared by few other languages and is one of the strengths of FORTH. Functions to define one, two, three, and four dimensioned arrays will be presented here. Careful study of the program will show the underlying principles, which can also be applied to arrays with five or more dimensions. [...]  »

p.26 ROM Byte-Finder for the Apple II (p.243 in reprint volume 5)

p.26 ROM Byte-Finder for the Apple II (p.243 in reprint volume 5)

[author : Stephen E. Bach] #Listing #Assembly

p.27 The Errata of Computer Programming (p.244 in reprint volume 5)

p.27 The Errata of Computer Programming (p.244 in reprint volume 5)

[author : Donald E. Knuth ] #Book #Programming #Listing #Assembly

Extract : «  This report lists all corrections and changes of Volumes 1 and 3 of The Art of Computer Programming, as of January 5, 1979. This updates the previous list in report CS551, May 1976. The second edition of Volume 2 has been delayed two years due to the fact that it was completely revised and put in the TEX typesetting language; since publication of this new edition is not far off, no changes to Volume 2 are listed here. [...]  »

p.40 Random Ruminations of Networks of the Future (p.257 in reprint volume 5)

p.40 Random Ruminations of Networks of the Future (p.257 in reprint volume 5)

[author : Jonathan Sachs] #Networks #Anticipation

Extract : «  In the past, computers have been attractive only to those oddballs who were interested in computer hardware or software. Networking can make them attractive to everyone who needs to deal with information by making them potential tools for processing information about the world at large. This promises to be the first development that makes computers directly useful to a large proportion of mankind.

There has been a great deal of speculation (and some research) on this question of how computers will affect the quality of life. Scenarios run the gamut from a plugged-in society where everyone is in touch with everything, to a totally dehumanized society where people interact with machines to the exclusion of one another. For a thorough and responsible (but highly readable) study of the issues, see The Network Nation by Hiltz and Turoff (Addision-Wesley Publishing Company).

Networks must be not only useful, but usable by the public, or they will win little acceptance. What do I mean by “the public?” I mean: a substantial proportion of everyone who lives in the part of the world we’re considering. Here are some important characteristics of the public a successful network must serve: [...]  »

p.42 Displaying 2 Columns with North Star (p.259 in reprint volume 5)

p.42 Displaying 2 Columns with North Star (p.259 in reprint volume 5)

[author : O. K. Hudson] #Listing #Assembly

Extract : «  [...] Attached please find an 8080 Assembly listing for making a North Star Disk display its catalogue in two columns. [...]  »

p.43 A Versatile Memory Dump in BASIC (p.260 in reprint volume 5)

p.43 A Versatile Memory Dump in BASIC (p.260 in reprint volume 5)

[author : Hal Knippenberg] #Listing #Assembly

Extract : «  I am often asked how to develop memory dump programs. The main complaint is that most memory dump programs are too specialized-they work only in one mode. For instance, they will dump Hex when you want Decimal. Or they will dump Octal when you want Hex. [...]  »

p.44 Conversion: ALS-8 to CP/M (p.261 in reprint volume 5)

p.44 Conversion: ALS-8 to CP/M (p.261 in reprint volume 5)

[author : Edward Elizondo] #Listing #Assembly

Extract : «  [...] ALS8CPM successfuhy converts the bulk of ah ALS-8 statements to a form digestible by the CP/M ASM. Using ALS8CPM, the CUTER source files (total size = 58K) were converted with only seven residual errors flagged by ASM on reassembly. The program is fairly straightforward and fully commented, so it can easily be modified if desired. [...]  »

p.47 Algorithm: A Monthly Algorithm Column (p.264 in reprint volume 5)

p.47 Algorithm: A Monthly Algorithm Column (p.264 in reprint volume 5)

[author : Dennis Allison] #Listing #C #Algorithm

Extract : «  My old friend, Sylvan Rubin, sent on to me a major improvement in the nonrecursive merge program published in DDJ # 44. Rather than build the merged list backwards and then, later, reverse it, he builds it in the right order to begin with. This cuts the number of assignments per data element from 9.5 to 4.5 assuming randomly distributed data. He also improved the control structure a bit to eliminate some tests. All in all a much better program [...]  »