doc: Add RFC documents

1 files changed, 395 insertions, 0 deletions

diff --git a/doc/rfc/rfc7.txt b/doc/rfc/rfc7.txt
new file mode 100644
index 0000000..2c8914c
--- /dev/null
+++ b/doc/rfc/rfc7.txt
@@ -0,0 +1,395 @@
+
+
+
+
+
+
+Network Working Group                                         G. Deloche
+Request for Comment: 7           University of California at Los Angeles
+NIC: 4693                                                       May 1969
+
+
+                           Host-Imp Interface
+
+
+
+      G. Deloche      -->  Prof. J. Estrin
+                           Prof. L. Kleinrock
+                           Prof. B Bussel
+                           D. Mandell
+                           S. Crocker
+                           L. Bonamy
+
+
+   Object: Arpa Network - Specification Outlines for Host-IMP (HI)
+   Interface Programs.
+
+
+
+                                  Outline
+
+   I.  Introduction
+
+   II.  Scope of the software organization.
+           II-1    Network program
+           II-2    Handler program
+
+   III.  Questions
+
+
+
+
+
+   [The original of RFC 7 was hand-written, and only partially illegible
+   copies exist.  RFC 7 was later typed int NLS by the Augmentation
+   Research Center (ARC) at SRI.  The following is the best
+   reconstruction we could do.  RFC Editor.]
+
+
+
+
+
+
+
+
+
+
+
+Deloche                                                         [Page 1]
+
+RFC 7                      Host-IMP Interface                   May 1969
+
+
+I.  Introduction
+
+   This paper is concerned with the preliminary software design of the
+   Host IMP interface.  Its main purpose is on the one hand to define
+   functions that will be implemented, and on the other hand to provide
+   a base for discussions and ...(unreadable).
+
+   This study is based upon a study of the BBN Report No. 763.
+
+II.  Scope of the software organization.
+
+   The system is based upon two main programs: the Handler program that
+   drives the channel hardware unit, and the Network program which
+   carries out the user's transmission requests.
+
+   As the communication is full duplex, each of these programs can be
+   viewed as divided into two parts: one is concerned with the output
+   data, the other with the input. (See Fig. 1)
+
+   These two programs exchange data through a pool of buffers, and
+   logical information through an interface table.
+
+   In the following we only focus on the output part of each program
+   (See Fig. 2).  The input part would be very similar.
+
+II-1.   Network program.
+
+II-1-1. Multiplex function.
+
+   This program multiplexes the outgoing messages (and distributes the
+   incoming messages).  The multiplexing consists in stacking up all the
+   user's (or caller, or party) requests and filling up the pool of
+   buffers so as to keep the handler busy emitting.
+
+   Multiplexing (and distribution) is based on the link identification
+   numbers.  (Link = logical connection between two users).  The
+   multiplexing problem is closely related to the interface between a
+   user's program and the network program, that is in
+   fact...(unreadable) operating system (See below: Questions).
+
+II-1-2.  Output message processing.
+
+   When a user's program wants to send out text it should indicate the
+   following information (through a macro, or as call parameters): text
+   location, text length in bytes, and destination.
+
+
+
+
+
+
+Deloche                                                         [Page 2]
+
+RFC 7                      Host-IMP Interface                   May 1969
+
+
+   Using these data the Network program:
+
+      *  prepares a 16 bit Host heading (1 bit: trace, 2 bits: spares, 8
+         bits: link identification no., 5 bits: destination host)
+
+      *  inserts a 16 bits marking between the header and the text so as
+         to start the text at a word boundary.  This marking consists of
+         a one preceding the first bit of the text and, in turn,
+         preceded by fifteen zeros to fill up the gap.
+
+      *  checks the length of the user's text - if it exceeds 1006 bytes
+
+          +-                                                     -+
+          |8080 (max host message length) - 32 (heading + marking)|
+          |-------------------------------------------------------|
+          |                8 (byte = 8 bits)                      |
+          +-                                                     -+
+
+   the program breaks down the text into a sequence of messages whose
+   maximum length is 1006 bytes - Each of these messages is preceded by
+   a heading as explained above.
+
+   Remark: in that case one of the heading space bits could be used for
+   indicating that several messages belong to the same text.
+
+      *  _transcodes_ the EBCDIC characters constituting the messages
+         into ASCII characters.
+
+      *  _fills_ the buffers of the pool with the content of the
+         messages.
+
+      *  _updates_ the content of the interface table and moves the
+         filling pointers (see below).
+
+II-2.  Handler program.
+
+   This program is initiated either by the network program, or by the
+   I/O interrupt.
+
+   This program will be very short.  It will be coded in master mode
+   (privileged instructions) and should be integrated in the I/O
+   supervisor of the operating system.
+
+
+
+
+
+
+
+
+
+Deloche                                                         [Page 3]
+
+RFC 7                      Host-IMP Interface                   May 1969
+
+
+   This program:
+
+      *  _controls_ the channel hardware unit.  It initiates the
+         emission, eventually provides data chaining between the
+         buffers, tests the different device status upon receiving an
+         interrupt.
+
+      *  _empties_ the buffers that are filled up by the network
+         program.
+
+      *  _explores_ and _updates_ the interface table (see below).
+
+      *  can eventually insure a control transmission procedure with the
+         IMP (See Questions).
+
+II-3  Buffers and Interface Table.
+
+II-3-1  Buffers.
+
+   They should be large enough for containing the maximum host message
+   text + heading and marking (1006 + 4 = 1010 bytes).
+
+   Consequently the buffer size could be chosen equal to 256 words (1024
+   bytes).  As for the buffer number it will determine the link
+   utilization frequency -
+
+II-3-2  Interface table.
+
+   It is through this table that the network program informs the handler
+   with the location and length of the emitting data.
+
+   This table could be a ring table with 2 pointers: one for filling,
+   the other for extracting.  They are respectively updated by the
+   network and the handler program.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Deloche                                                         [Page 4]
+
+RFC 7                      Host-IMP Interface                   May 1969
+
+
+                      [Length] of the message
+                           contained
+                           in the buffer
+                               ^
+                               |
+           +--------------+----------+
+           | Buffer addr. | nb bytes |
+           +--------------+----------+
+           |              |          | <== Filling pointer
+           +--------------+----------+         |
+           |                         |         V
+           |                         |
+           //                        //
+           |                         |
+           |                         |
+           |                         |
+           +--------------+----------+
+           | Buffer addr. | nb bytes | <== eEtracting pointer
+           +--------------+----------+         |
+           | Buffer addr. | nb bytes |         V
+           +--------------+----------+
+
+
+
+III.  Questions.
+
+III-1.  Why is there not a simple control procedure between the HOST and
+        the IMP?  What happens if a message, issued from the HOST,
+        reaches the IMP with an error due to the transmission?
+
+   From the BBN specifications it appears that this error will be
+   transmitted as far [as] the receiving HOST.
+
+   In that case must an HOST-HOST control procedure be provided?
+
+III-2.  Where will the special channel hardware unit be connected
+        (MIOP/SIOP)?
+
+   How will this device be notified of an outgoing message end in order
+   to start the padding?
+
+   (The program will provide to the MIOP SIOP the number of bytes of the
+   outgoing message, and will receive back an interrupt when the last
+   byte is sent out.  Is it that signal which will be also sent to the
+   special device?)
+
+   Vice versa how does the Handler know the length of the incoming
+   message?  From the contents of the previous one or should this
+
+
+
+Deloche                                                         [Page 5]
+
+RFC 7                      Host-IMP Interface                   May 1969
+
+
+   program always ready to receive a message of maximum length?  (Then
+   an interrupt should be triggered when the real end is detected by the
+   hardware).
+
+III-3.  When does the Gordo documentation will be available in order to
+        design the user-network program interface.  What are the
+        mechanisms for program initiations, transferring parameters from
+        one program to another, etc...
+
+
+
+
+
+
+                           HOST (Sigma 7) <--|/|--> Outside world
+   Users                                     |/|
+    |                                        |/|
+    |                                        |/|   Special  Standard
+    V                                        |/|      |       |
+         +--------------+   +------------+   |/|      V   |   V
+    o----|              |   |            |   |/|   +------+------+
+         |   Output     |-->|   Output   |-->|/|-->|      |      |-->IMP
+    . . .|              |   |            |   |/|   |             |
+         |              |   |            |   |/|   |      |      |
+    o----| (Multiplex)  |   |            |   |/|   |             |
+         |_ _ _ _ _ _ _ |   |_ _ _ _ _ _ |   |/|   | _ _ _| _ _ _|
+    o----|              |   |            |   |/|   |      |      |
+         |   Input      |<--|    Input   |<--|/|<--|             |<--IMP
+    . . .|              |   |            |   |/|   |      |      |
+         |              |   |            |   |/|   |             |
+    o----|(Distribution)|   |            |   |/|   +------|------+
+         |              |   |            |   |/|       HARDWARE
+         +--------------+   +------------+   |/|       Interface
+             NETWORK          HANDLER        |/|
+             Program          Program        |/|
+                                             |/|    (Fig. 1)
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Deloche                                                         [Page 6]
+
+RFC 7                      Host-IMP Interface                   May 1969
+
+
+                                                   +------------------+
+                                                   | | |              |
+                                                   | | | interface    |
+                                                   | | |              |
+                                                   |                  |
+                                                   | ====> Data       |
+                                                   |                  |
+                                                   | ----- Logical    |
+                                                   |       information|
+                                                   +------------------+
+
+                      + - - - - - - - - - - - - - -+
+                      |                            |
+                              interface table
+                      |        +----------+        |               | |
+        | |              +---->|          |<----+                  | |
+        | |           |  |     +----------+     |  |   interrupt   | |
+        | |           ^  |                      |     +----<-------| |
+        | |           |  |    +-          -+    |  |  |            | |
+        | |           |  V    |  _________ |    V  V  V            | |
+   o----| |-+  +---------+-+  | |         ||  +-+--+--+---+        | |
+        | |  \ |+---------+|  | |_________||  |+---------+|        | |
+        | |   \||         ||  |            |  ||         ||        | |
+        | |    +|         ||  | - - - - - -|  ||         ||        | |
+        | |    ||         ||  |            |  ||         ||        | |
+    - - - - - -|| NETWORK ||=>-  _________ -=>|| HANDLER ||=======>| |
+        | |    +| Progr.  ||  | |         ||  || Progr.  ||        | |
+        | |   /||         ||  | |_________||  ||         ||        | |
+        | |  / |+---------+|  |            |  |+---------+|        | |
+   o----| |-+  +-----------+  |  _________ |  +----+------+        | |
+   ^    | |                   | |         ||       |               | |
+   |    | |                   | |_________||       +--->---------->| |
+   |     ^                    +-    ^     -+         Commands      | |
+   Users |                          |                              | |
+         |                    Pool of buffers                      | |
+       User's                                                       ^
+      Interface                                                     |
+                                                              Hardware
+                                                             Interface
+
+                           (Fig. 2)
+
+
+
+
+         [ This RFC was put into machine readable form for entry ]
+   [ into the online RFC archives by Bob German & Lorrie Shiota 1/02 ]
+
+
+
+
+Deloche                                                         [Page 7]
+