GENWiki

Premier IT Outsourcing and Support Services within the UK

User Tools

Site Tools

Problem, Formatting or Query -  Send Feedback

Was this page helpful?-10+1


rfc:rfc109

Network Working Group J. Winett Request for Comments: 109 MIT Lincoln Laboratory NIC: 5805 24 March 1971

        Level III Server Protocol for the Lincoln Laboratory
                            360/67 Host

Disclaimer

 This material has not been reviewed for public release and is
 intended only for use with the ARPA network.  It should not be quoted
 or cited in any publication not related to the ARPA network.

Introduction

 The Lincoln Laboratory IBM 360/67 is connected to the ARPA network
 and acts as a serving host providing access to the CP-67 virtual
 machine operating system.  Upon completion of the Login procedure,
 users have control of a 360 virtual machine through a virtual 1052
 online console.  Attached to the virtual machine is a virtual card
 reader, card punch and line printer, and a number of disk storage
 devices.  The 360 virtual machine can be either a virtual 360/67 with
 dynamic address translation hardware or a standard System/360.  Most
 users run a standard 360 with 256K bytes of virtual memory and
 operate the CMS conversational monitor system.  CMS provides
 facilities for file creation, maintenance and manipulation, program
 development, debugging and execution, and a number of other useful
 utility functions.  The section in the Network Notebook on the
 Lincoln Laboratory 360/67 more fully describes the facilities
 available.

Network Control Program

 All communication with the 360/67 through the IMP are processed by a
 Network Control Program (NCP).  The NCP operates with the Host-Host
 Protocol described in the Network Working Group Document No. 1 dated
 3 August 1970.

Initial Connection Protocol

 To create a virtual machine from the network, a pair of connections
 must be made with the LOGGER.  The sockets to be used are assigned
 following the Initial Connection Protocol (ICP).  The LOGGER is
 enabled and waiting for an RTS control command for socket X'0A 0000
 01'.  This ICP socket corresponds to home X'0A', user X'0000', and
 tag X'01' (send gender).  Requests for connection on the ICP socket
 are stacked until it becomes free.  If the LOGGER is willing to

Winett [Page 1] RFC 109 Level II Server Protocol 24 March 1971

 service another network user, a 32 bit socket ID of a receive socket
 will be sent over this initial connection and the ICP socket will
 then be closed.  If the LOGGER is not willing to service another
 network user, it will not complete the initial connection for the ICP
 socket and will refuse the request by closing the connection without
 completing it.

LOGGER Protocol

 Once a pair of user sockets have been assigned, the connection
 protocol should be completed on these sockets.  The LOGGER then
 expects to receive (on the receive socket) one 8-bit byte indicating
 the data type which characterizes the transmission code used to
 communicate with the network user over this pair of sockets.  A code
 of X'01' implies 7 bit ASCII code in 8-bit bytes with the leading bit
 zero.  A code of X'02' implies 8-bit EBCDIC code.  When the data type
 code is received, the LOGGER will echo back the data type code over
 the send socket followed by the message:
          LINCOLN LABORATORY CP-67 ONLINE NL
 in the appropriate code.  (In ASCII, NL is transmitted as CR LF).
 The procedure continues according to the normal CP-67 login protocol
 with the LOGGER performing an additional function of mapping network
 userids and passwords into valid CP-67 userids and passwords.  This
 mapping is specified by entries in a file (the LOGGER FILE) which the
 LOGGER accesses.  If a network userid does not match an entry in the
 file or if the password given does not match the corresponding
 network password, the usual CP responses will be sent to the users.
 Thus network access to the Lincoln Laboratory system is restricted to
 those accounts for which an appropriate entry has been made in the
 LOGGER FILE.
 It should be noted that CP transmits a BYP code (Bypass) to suspend
 the printing of characters keyed while a password is being entered.
 After the password has been entered, CP transmits a RES code
 (Restore) to resume the printing when characters are keyed.  When
 communicating in ASCII, these character codes are converted to X'FF'
 since no corresponding ASCII code is defined.  Refer to the Network
 Resource Notebook for more details on CP-67 and on CMS.

The NET Account

 Lincoln Laboratory is providing one account which can be used by
 network users to familiarize themselves with our time-sharing system.
 The userid of this account is NET and the password is ARPA.  This
 account has 900 records of storage, which can store approximately

Winett [Page 2] RFC 109 Level II Server Protocol 24 March 1971

 720,000 characters.  NET users are free to ERASE any file on this
 account since many different people may use this account.

The SERVER Protocol

 CP-67 operates on a line at a time, i.e., a group of characters are
 processed as a line and not as a sequence of individual characters.
 Also, the system does normally buffer input lines, that is, input is
 not normally entered until requested by a read from the system.  With
 IBM 2741 or 1052 terminals, the keyboard is locked until a read is
 requested.  The virtual terminals through which network users have
 access to the CP-67 system have been designed to support either a
 line oriented terminal or a character oriented terminal.  When CP
 requests a line of input, the SERVER transmits a prompting code
 X'80'.  This character can be used to signal a user process to change
 transmission modes and to transmit an input line.  Characters
 received by the SERVER are buffered until a NL character is received.
 Lines received can then be used to satisfy CP requests for an input
 line.
 CP may send out lines which may or may not end with a NL character.
 If a line does not end with a NL character, the prompting character
 will naturally be sent following the output line to request input to
 a CP process.
 When a user wishes to interrupt a CP process, i.e., to change modes,
 an interrupt code X'80' should be sent to the SERVER.  This code will
 result in an asynchronous interrupt being sent to the running
 process, stimulating the pressing of the 'attention' button on a 2741
 terminal.  Together with the transmission of the interrupt code, the
 user should cause an INS to be sent over the send link.  This signal
 will be synchronized with the interrupt code.  If the interrupt code
 has not yet been received and processed, all characters buffered and
 those received before the receipt of the interrupt code will be
 flushed, i.e., deleted.  When the interrupt code is received, it will
 be paired with the previously received INS.  If an INS is received
 after an interrupt code has been received and processed, the INS will
 be paired with this previously received interrupt code.
 If CP has a line to send to a user after it has requested an input
 line but before it has received any input, the SERVER will transmit
 an INS on the user's receive link to notify the user that previously
 sent prompting character should be retracted and that a line has been
 or will be sent to the user.  This message line is called a
 "warning".

Winett [Page 3] RFC 109 Level II Server Protocol 24 March 1971

Graphic and Control Codes

 Figure 1 gives the 8-bit codes for the EBCDIC graphics and controls.
 Figure 2 gives the 7-bit codes for the ASCII graphics and controls.
 The controls are tabulated and compared in Figure 3.  The standard
 interpretation of the ASCII controls are given in Figure 4.
 There are 4 ASCII codes which do not have a corresponding graphic or
 control in the EBCDIC code.  The EBCDIC codes given to these codes
 are as follows:
                 |     Hex Code
           ASCII |-------+--------
          Symbol | ASCII | EBCDIC
          -------+-------+--------
             DC3 |  13   |  3A
                 |       |
              `  |  60   |  70
                 |       |
              \  |  5C   |  71
                 |       |
              ^  |  5E   |  72
 There are 29 EBCDIC graphics codes and 19 EBCDIC control codes which
 do not have a corresponding graphic or control in the ASCII code.  In
 addition, there are 84 other EBCDIC codes whose interpretation is
 unspecified.  Four of these codes have been chosen to correspond to
 the ASCII control and ASCII graphics which do not have a
 corresponding EBCDIC code.  When converting EBCDIC codes to ASCII
 codes, the remaining 80 codes plus the 29 EBCDIC graphics and 18
 EBCDIC controls (not counting NL) are converted into the code X'FF'.
 The NL character is treated specially.  The NL character, EBCDIC code
 X'15', is converted into the two character sequence CR LF, i.e.,
 ASCII X'0D 0A'.  As stated above, the code X'80' is transmitted as a
 prompting character whenever CP requests an input line.
 On converting from ASCII to EBCDIC, if any code other than the 128
 ASCII codes, or the interrupt codem X'80', is received, it is
 converted to the code X'FF'.  In addition , whenever the two ASCII
 characters CR LF are found sequentially in the input stream, they are
 converted into the single EBCDIC character NL.
 [In Figure 1, positions shown as "[?]" cannot be printed in ASCII.]

Winett [Page 4] RFC 109 Level II Server Protocol 24 March 1971

      0 0  0   0   0   0   0   0   0   1   1   1   1   1   1   1   1
      1 0  0   0   0   1   1   1   1   0   0   0   0   1   1   1   1
      2 0  0   1   1   0   0   1   1   0   0   1   1   0   0   1   1
      3 0  1   0   1   0   1   0   1   0   1   0   1   0   1   0   1
 4567+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 0000|NUL|DLE|DS |   |SP | & | - |   |   |   |[?]|[?]|   |   |   | 0 |
     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 0001|SOH|DC1|SOS|   |   |   | / |   | a | j |[?]|[?]| A | J |   | 1 |
     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 0010|STX|DC2|FS |SYN|   |   |   |   | b | k | s |[?]| B | K | S | 2 |
     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 0011|ETX|TM |   |   |   |   |   |   | c | l | t |[?]| C | L | T | 3 |
     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 0100|PF |RES|BYP|PN |   |   |   |   | d | m | u |[?]| D | M | U | 4 |
     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 0101|HT |NL |LF |RS |   |   |   |   | e | n | v |[?]| E | N | V | 5 |
     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 0110|LC |BS |ETB|UC |   |   |   |   | f | o | w |[?]| F | O | W | 6 |
     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 0111|DEL|IL |ESC|EOT|   |   |   |   | g | p | x |[?]| G | P | X | 7 |
     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 1000|   |CAN|   |   |   |   |   |   | h | q | y |[?]| H | Q | Y | 8 |
     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 1001|   |EM |   |   |   |   |   |   | i | r | z |[?]| I | R | Z | 9 |
     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 1010|SMM|CC |SM |   |[1]| ! |   | : |   |   |   |   |   |   |   |   |
     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 1011|VT |CU1|CU2|CU3| . | $ | , | # | { | } |[?]|[?]|   |   |   |   |
     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 1100|FF |IFS|   |DC4| < | * | % | @ |[?]|[?]|[?]|[?]|   |   |   |   |
     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 1101|CR |IGS|ENQ|NAK| ( | ) | _ | ' |[?]|[?]| [ | ] |   |   |   |   |
     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 1110|SO |IRS|ACK|   | + | ; | > | = |[?]|[?]|[?]|[?]|   |   |   |   |
     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
 1111|SI |IUS|BEL|SUB| | |[2]| ? | " |[?]|[?]|[?]|[?]|   |   |   |   |
     +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
                       +---+---+---+---+---+---+---+---+
                       | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
                       +---+---+---+---+---+---+---+---+
                                 Code Structure
                                    Figure 1.
          Extended Binary-Coded Decimal Interchange Code (EBCDIC)

Winett [Page 5] RFC 109 Level II Server Protocol 24 March 1971

          8 0   0   0   0   0   0   0   0
          7 0   0   0   0   1   1   1   1
          6 0   0   1   1   0   0   1   1
          5 0   1   0   1   0   1   0   1
      4321+---+---+---+---+---+---+---+---+
      0000|NUL|DLE|SP | 0 | @ | P | ` | p |
          +---+---+---+---+---+---+---+---+
      0001|SOH|DC1| ! | 1 | A | Q | a | q |
          +---+---+---+---+---+---+---+---+
      0010|STX|DC2| " | 2 | B | R | b | r |
          +---+---+---+---+---+---+---+---+
      0011|ETX|DC3| # | 3 | C | S | c | s |
          +---+---+---+---+---+---+---+---+
      0100|EOT|DC4| $ | 4 | D | T | d | t |
          +---+---+---+---+---+---+---+---+
      0101|ENQ|NAK| % | 5 | E | U | e | u |
          +---+---+---+---+---+---+---+---+
      0110|ACK|SYN| & | 6 | F | V | f | v |
          +---+---+---+---+---+---+---+---+
      0111|BEL|ETB| ' | 7 | G | W | g | w |
          +---+---+---+---+---+---+---+---+
      1000|BS |CAN| ( | 8 | H | X | h | x |
          +---+---+---+---+---+---+---+---+
      1001|HT |EM | ) | 9 | I | Y | i | y |
          +---+---+---+---+---+---+---+---+
      1010|LF |SUB| * | : | J | Z | j | z |
          +---+---+---+---+---+---+---+---+
      1011|VT |ESC| + | ; | K | [ | k | { |
          +---+---+---+---+---+---+---+---+
      1100|FF |FS | , | < | L | \ | l | | |
          +---+---+---+---+---+---+---+---+
      1101|CR |GS | - | = | M | ] | m | } |
          +---+---+---+---+---+---+---+---+
      1110|SO |RS | . | > | N | ^ | n | ~ |
          +---+---+---+---+---+---+---+---+
      1111|SI |SU | / | ? | O | _ | o |DEL|
          +---+---+---+---+---+---+---+---+
  +---+---+---+---+---+---+---+---+---+---+---+---+
          | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 |
          +---+---+---+---+---+---+---+---+
                   Code Structure
                      Figure 2.
 USA Standard Code for Information Interchange (USASCII)

Winett [Page 6] RFC 109 Level II Server Protocol 24 March 1971

 CAT     EBCDIC  ASCII   TTY     PTTC    FUNCTION
         NUL     NUL     NULL            Null
 CC      SOH     SOH     SOM             Start of Heading
 CC      STX     STX     EOA     EOA (D) Start of Text
 CC      ETX     ETX     EOM             End of Text
 DC      PF                      PF      Punch Off
 FE      HT      HT      H.TAB   TAB     Horizontal Tab
 GR      LC                      LC      Lower Case
         DEL     DEL     RUBOUT  DEL     Delete
         SMM                             Start of Manual Message
 FE      VT      VT      V.TAB           Vertical Tab
 FE      FF      FF      FORM            Form Feed
 FE      CR      CR      RETURN          Carriage Return
 GR      SO      SO      SO              Shift Out
 GR      SI      SI      SI              Shift In
 CC      DLE     DLE     DC0             Data Link Escape
 DC      DC1     DC1     X-ON            Device Control 1
 DC      DC2     DC2     TAPE ON         Device Control 2
         TM                              Tape Mark
 DC      RES                     RES     Restore
 FE      NL                      NL      New Line
 FE      BS      BS              BS      Backspace
         IL                      IL      Idle
         CAN     CAN     FE0     CAN     Cancel
         EM      EM      S1              End of Medium
         CC                              Cursor Control
 CU      CU1                             Customer Use 1
 IS      IFS     FS      S4              Info. Field Separator
 IS      IGS     GS      S5              Info. Group Separator
 IS      IRS     RS      S6              Info. Record Separator
 IS      IUS     US      S7              Info Unit Separator
 ED      DS                              Digit Select
 ED      SOS                             Start of Significance
 ED      FS                              Field Separator
 DC      BYP                     BYP     Bypass
 FE      LF      LF      LF      LF      Line Feed
 CC      ETB     ETB     LEM     EOB (B) End of Text Block
         ESC     ESC     S3      PRE     Escape
         SM                              Set Mode
 CU      CU2                             Customer Use 2
 CC      ENQ     ENQ     WRU             Enquiry
 CC      ACK     ACK     RU      (Y)     Acknowledge
         BEL     BEL     BELL            Bell
 CC      SYN     SYN     SYNC            Synchronous Idle
 DC      PN                      PN      Punch On
 DC      RS                      RS      Reader Stop
 GR      UC                      UC      Upper Case

Winett [Page 7] RFC 109 Level II Server Protocol 24 March 1971

 CC      EOT     EOT     EOT     EOT (C) End of Transmission
 CU      CU3                             Customer Use 3
 DC      DC4     DC4     TAPE OFF        Device Control 4
 CC      NAK     NAK     ERROR   (N)     Negative Acknowledge
         SUB     SUB     S2              Substitute
 DC              DC3     X-OFF           Device Control 3
                     Figure 3
              Control Functions Compared
 CC   (Communication Control).  A functional character intended to
       control or facilitate transmission of information over
       communication networks.
 FE   (Format Effector).  A functional character which controls the
       layout or positioning of information in printing or display
       devices.
 IS   (Information Separator).  A character which is used to separate
       and qualify information in a logical sense.  There is a group
       of four such characters, which are to be used in a hierarchical
       order.
 DC   (Device Control).  A functional character used for the control
       of ancillary devices associated with data processing of
       telecommunication systems, more especially switching devices
       "on" and "off".
 ED   (Edit and Mark).  A control character used by the System/360
       Edit and Mark (EDMK) instruction for the formatting of
       alphanumeric fields.
 GB   (Graphic Control).  A control character indicating that the code
       combinations which follow are to be interpreted in a particular
       code table, depending upon the particular control character.
 CU   (Customer Use).  A character excluded from future assignment by
       IBM.  These "protected" codes are intended for use by customer
       systems so that their use will not conflict with a possible
       future IBM use.
                         Figure 3 (Continued)
                   Categories of Control Functions

Winett [Page 8] RFC 109 Level II Server Protocol 24 March 1971

 NUL  (Null).  The all-zeros character which may serve to accomplish
       time fill and media fill.
 SOH  (Start of Heading).  A communication control character used at
       the beginning of a sequence of characters which constitute a
       machine-sensible address or routing information.  Such a
       sequence is referred to as the _heading_.  An STX character has
       the effect of terminating a heading.
 STX  (Start of Text).  A communication control character which
       precedes a sequence of characters that is to be treated as an
       entity and transmitted through to the ultimate destination.
       Such a sequence is referred to as _text_.  SIX may be used to
       terminate a sequence of characters started by SOH.
 ETX  (End of Text).  A communication control character used to
       terminate a sequence of characters started with STX and
       transmitted as an entity.
 EOT  (End of Transmission).  A communication control character used
       to indicate the conclusion of a transmission, which may have
       contained one or more texts and any associated headings.
 ENQ  (Enquiry).  A communication control character used in data
       communication systems as a request for a response from a remote
       station.  It may be used as a "Who Are You" (WRU) to obtain
       identification, or may be used to obtain station status, or
       both.
 ACK  (Acknowledge).  A communication control character transmitted by
       a receiver as an affirmative response to a sender.
 BEL  (Bell).  A character for use when these is a need to call for
       human attention.  It may control alarm or attention devices.
 BS   (Backspace).  A format effector which controls the movement of
       the printing position one printing space backward on the same
       printing line (applicable also to display devices).
 HT   (Horizontal Tabulation).  A format effector which controls the
       movement of the printing position to the next in a series of
       predetermined positions along the printing line (applicable
       also to display devices and the skip function on punched
       cards.)
 LF   (Line Feed).  A format effector which controls the movement of
       the printing position to the next printing line (also
       applicable to display devices).

Winett [Page 9] RFC 109 Level II Server Protocol 24 March 1971

 VT   (Vertical Tabulation).  A format effector which controls the
       movement of the printing position to the next in a series of
       predetermined printing lines (also applicable to display
       devices).
 FF   (Form Feed).  A format effector which controls the movement of
       the printing position to the first predetermined printing line
       on the next form or page (also applicable to display devices).
 CR   (Carriage Return).  A format effector which controls the
       movement of the printing position to the first printing
       position on the same printing line (also applicable to display
       devices).
 SO    (Shift Out).  A control character indicating that the code
       combinations which follow shall be interpreted as outside of
       the character set of the standard code table until a Shift In
       Character is reached.
 SI    (Shift In).  A control character indicating that the code
       combinations which follow shall be interpreted according to the
       standard code table.
 DLE   (Data Link Escape).  A communication control character which
       will change the meaning of a limited number of contiguously
       following characters.  It is used exclusively to provide
       supplementary controls in data communication networks.
 DC1, DC2, DC3, DC4 (Device Controls).  Characters for the control of
       ancillary devices associated with data processing or
       telecommunication systems, more especially switching devices
       "on" and "off".  (If a single "stop" control is required to
       interrupt of turn off ancillary devices, DC4 is the preferred
       assignment.)
 NAK  (Negative Acknowledge).  A communication control character
       transmitted by a receiver as a negative response to a sender.
 SYN   (Synchronous Idle).  A communication control character used by
       a synchronous transmission system in the absence of any other
       character to provide a signal from which synchronism may be
       achieved or retained.

Winett [Page 10] RFC 109 Level II Server Protocol 24 March 1971

 ETB  (End of Transmission Block).  A communication control character
       used to indicate the end of a block of data for communication
       purposes.  ETB is used for blocking data where the block
       structure is not necessarily related to the processing format.
 CAN  (Cancel).  A control character used to indicate that the data
       with which it is sent is in error or is to be disregarded.
 EM   (End of Medium).  A control character associated with the sent
       data which may be used to identify the physical end of the
       medium, or the end of the used, or wanted, portion of
       information recorded on a medium.  (The position of this
       character does not necessarily correspond to the physical end
       of the medium.
 SS   (Start of Special Sequence).  A control character used to
       indicate the start of a variable length sequence of characters
       which have special significance or which are to have special
       handling.
 ESC  (Escape).  A control character intended to provide code
       extension (supplementary characters) in general information
       interchange.  The Escape character itself is a prefix affecting
       the interpretation of a limited number of contiguously
       following characters.
 FS   (File Separator), GS (Group Separator), RS (Record Separator)
       and US (Unit Separator).  These information separators may be
       used within data in optional fashion, except that the
       hierarchical relationship shall be : FS is the must inclusive,
       then GS, then RS, and US is least inclusive.  (The content and
       length of a File, Group, Record, or Unit are not specified.)
 DEL  (Delete).  This character is used primarily to "erase" or
       "obliterate" erroneous or unwanted characters in perforated
       tape.  (In the strict sense, DEL is not a control character.)
                             Figure 4
                      ASCII Control Functions

Winett [Page 11] RFC 109 Level II Server Protocol 24 March 1971

Endnotes

 [1] - Cent sign
 [2] - Logical not ("bent bar")
 [?] - Graphics not in ASCII.  See Postscript or PDF version of
       this document.
        [This RFC was put into machine readable form for entry]
        [into the online RFC archives by Lorrie Shiota, 10/02]

Winett [Page 12]

/data/webs/external/dokuwiki/data/pages/rfc/rfc109.txt · Last modified: 2009/08/21 19:22 (external edit)