Kermit 2 1986, FIZYKA ogólnie, Sieci Komputerowe

[ Pobierz całość w formacie PDF ]
KERMIT PROTOCOL MANUAL
Sixth Edition
Frank da Cruz
Columbia University Center for Computing Activities
New York, New York 10027
June 1986
Copyright (C) 1981,1986
Trustees of Columbia University in the City of New York
Permission is granted to any individual or institution to copy or
use this document and the programs described in it, except for
explicitly commercial purposes.
Table of Contents Page i
Table of Contents
1. Introduction 4
1.1. Background 4
1.2. Overview 4
2. Definitions 6
2.1. General Terminology 6
2.2. Numbers 6
2.3. Character Set 7
2.4. Conversion Functions 7
2.5. Protocol Jargon 8
3. System Requirements 9
4. Printable Text versus Binary Data 11
4.1. Printable Text Files 11
4.2. Binary Files 11
5. File Transfer 13
5.1. Conditioning the Terminal 14
5.2. Timeouts, NAKs, and Retries 14
5.3. Errors 15
5.4. Heuristics 15
5.5. File Names 16
5.6. Robustness 17
5.7. Flow Control 17
5.8. Basic Kermit Protocol State Table 18
6. Packet Format 20
6.1. Fields 20
6.2. Terminator 21
6.3. Other Interpacket Data 21
6.4. Encoding, Prefixing, Block Check 22
7. Initial Connection 23
8. Optional Features 27
8.1. 8th-Bit and Repeat Count Prefixing 27
8.2. Server Operation 28
8.2.1. Server Commands 29
8.2.2. Timing 30
8.2.3. The R Command 31
8.2.4. The K Command 31
8.2.5. Short and Long Replies 31
8.2.6. Additional Server Commands 32
8.2.7. Host Commands 34
8.2.8. Exchanging Parameters Before Server Commands 34
Table of Contents Page ii
8.3. Alternate Block Check Types 35
8.4. Interrupting a File Transfer 37
8.5. Transmitting File Attributes 37
8.6. Advanced Kermit Protocol State Table 45
9. Performance Extensions 49
9.1. Long Packets 49
9.2. Sliding Windows 52
9.2.1. Overall Sequence of Events 52
9.2.2. Questions and Answers about Sliding Windows 60
9.2.3. More Q-and-A About Windows 63
10. Kermit Commands 66
10.1. Basic Commands 66
10.2. Program Management Commands 66
10.3. Terminal Emulation Commands 67
10.4. Special User-Mode Commands 67
10.5. Commands Whose Object Should Be Specified 67
10.6. The SET Command 69
10.7. Macros, the DEFINE Command 71
11. Terminal Emulation 72
12. Writing a Kermit Program 74
12.1. Program Organization 74
12.2. Programming Language 76
12.3. Documentation 76
12.4. Bootstrapping 77
I. Packet Format and Types 78
II. List of Features 80
III. The ASCII Character Set 82
Index i
PREFACE TO THE SIXTH EDITION
The sixth edition (June 1986) of the Kermit Protocol Manual is being issued for
two major reasons: to correct minor errors in the fifth edition, and to include
new sections on two major protocol extensions: long packets and sliding win-
dows. No attempt has been made to reorganize, rewrite, or otherwise improve
the protocol manual. The Kermit protocol has been presented in an entirely
different -- hopefully more thorough, organized, coherent, and useful (if not
more formal) -- manner in the book, "Kermit, A File Transfer Protocol," by
Frank da Cruz, Digital Press, Bedford MA (1986), ISBN 0-932376-88-6, DEC order
number EY-6705E-DP. If you have the book, you won't need this protocol manual.
On the other hand, if you don't have the book, this manual should still contain
all the necessary information. The Kermit Protocol Manual will continue to be
freely distributed in perpetuity.
The bare-bones C-language Kermit program that appeared as an appendix in pre-
vious editions has been removed. It was not a particularly good example of how
to write a Kermit program, and made the manual unnecessarily thick. For sample
Kermit programs, see the source code for any of the hundreds of Kermit im-
plementations, or follow the program fragments in the book.
PREFACE TO THE FIFTH EDITION
The fifth edition (March 1984) attempts to clarify some fine points that had
been left ambiguous in the 4th edition, particularly with respect to when and
how prefix encoding is done, and when it is not, and about switching between
block check types. A mechanism is suggested (in the Attributes section) for
file archiving, and several attributes have been rearranged and some others
added (this should do no harm, since no one to date has attempted to implement
the attributes packet). A more complete protocol state table is provided, a
few minor additions are made to the collection of packet types.
PREFACE TO THE FOURTH EDITION
The fourth edition (November 1983) of the Kermit Protocol Manual incorporates
some new ideas that grew from our experience in attempting to implement some of
the features described in earlier editions, particularly user/server functions.
These include a mechanism to allow batch transfers to be interrupted gracefully
for either the current file or the entire batch of files; a "capability mask";
a protocol extension for passing file attributes. In addition, numbers are now
written in decimal notation rather than octal, which was confusing to many
readers. Also, several incompatible changes were made in minor areas where no
attempts at an implementation had yet been made; these include:
- The format and interpretation of the operands to the server commands.
- Usurpation of the reserved fields 10-11 of the Send-Init packet, and
addition of new reserved fields.
Most of the remaining material has been rewritten and reorganized, and much new
material added, including a section on the recommended vocabulary for documen-
tation and commands.
The previous edition of the Protocol Manual attempted to define "protocol ver-
[ Pobierz całość w formacie PDF ]
  • zanotowane.pl
  • doc.pisz.pl
  • pdf.pisz.pl
  • klobuckfatima.xlx.pl