summaryrefslogtreecommitdiff
path: root/doc/rfc/rfc12.txt
diff options
context:
space:
mode:
Diffstat (limited to 'doc/rfc/rfc12.txt')
-rw-r--r--doc/rfc/rfc12.txt339
1 files changed, 339 insertions, 0 deletions
diff --git a/doc/rfc/rfc12.txt b/doc/rfc/rfc12.txt
new file mode 100644
index 0000000..6ddc621
--- /dev/null
+++ b/doc/rfc/rfc12.txt
@@ -0,0 +1,339 @@
+
+
+
+
+
+
+Network Working Group M. Wingfield
+Request for Comments: 12 REVISED 26 August 1969
+
+
+ IMP-HOST INTERFACE FLOW DIAGRAMS
+
+ The following flow diagrams were extracted from the logic diagrams
+ provided in Appendix B of BBN Report No. 1822. These diagrams
+ indicate the logical sequence of hardware operations which occur
+ within the IMP-HOST interface. The logic names appearing in the
+ blocks correspond to the logic elements found in Appendix B.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Wingfield [Page 1]
+
+RFC 12 IMP-HOST INTERFACE FLOW DIAGRAMS 26 August 1969
+
+
+IMP to HOST Message
+ +----------+
+ | Start |
+ | Input |
+ +----------+
+ |
+ V
+ +------------------------+
+ | LAST <--0; IMPERR <--0 |
+ | PAD <--0; IN REQST <--0|
+ | COUNTER <--0 |
+ +------------------------+ +---+
+ |<----------------- | B |
+ V +---+
+ +--------------+
+ | RFNIB <-- 1 |
+ +--------------+
+ |<--------------+
+ V |
+ / \ |
+ / \ |
+ / THERE'S \ N |
+ \YOUR BIT /----------+
+ \=1 ? /
+ \ /
+ |
+ +------------------->V
+ | / \
+ +----+------+ N / \
+ | IMP ERROR |<------ / IMP \
+ | <--- 1 | \ READY /
+ +-----------+ \ ? /
+ \ /
+ | Y
+ V
+ / \
+ / \
+ +-----------+ Y / LAST \
+ | PAD <-- 1 |<-------\ IMP BIT /
+ +-----------+ \ =1? /
+ | \ / +---+
+ +------------------->|<-----------------| C |
+ V +---+
+ +-----------------------+
+ | PULSE SHIFT REG. | +---+
+ | INCREMENT COUNTER |------>| A |
+ | RFNTR <-- 0 | +---+
+ +-----------------------+
+
+
+
+Wingfield [Page 2]
+
+RFC 12 IMP-HOST INTERFACE FLOW DIAGRAMS 26 August 1969
+
+
+ +---+ +---+
+ | C | | A |
+ +-+-+ +-+-+
+ ^ |
+ | Y V
+ / \ / \
+ / \ N /WORD \
+ / PAD=1 \ <--------/ LENGTH \
+ \ ? / \ =1 /
+ \ / \ ? /
+ \ / \ /
+ | N |
+ V V
+ +---+ +----------------------+
+ | B | | INREQST <--1 |
+ +---+ +----------------------+
+ |<-----------+
+ V |
+ / \ |
+ /DATA \ |
+ /HAS BEEN \_N_____|
+ \ TAKEN /
+ \ ? /
+ \ /
+ V Y
+ +----------------------+
+ | INREQST <--0 |
+ +----------------------+
+ V
+ / \
+ / \ +------------+
+ / LAST = 1\----------->| END OF |
+ \ ? / | MESSAGE |
+ \ / +------------+
+ \ / ^
+ | N |
+ V |
+ / \ |
+ / \ |
+ / PAD = 1 \-------------------+
+ \ ? /
+ \ /
+ \ /
+ | N
+ V
+ +---+ +---------------------+
+ | B |<---------| CLEAR COUNTER |
+ +---+ +---------------------+
+
+
+
+Wingfield [Page 3]
+
+RFC 12 IMP-HOST INTERFACE FLOW DIAGRAMS 26 August 1969
+
+
+HOST TO IMP MESSAGE
+
+ +--------------+
+ | START OUTPUT |
+ +------+-------+
+ V
+ +------------------------+
+ | COUNTER <-- 1 |
+ | LSTWD <--0; BTAVL <--0 |
+ +-----------+------------+ +---+
+ |<--------------------| C |
+ V +---+
+ +-----------+------------+
+ | OUT REQST <-- 1 |
+ | CLEAR SHIFT REG. |
+ +-----------+------------+
+ +------------>|
+ | V
+ | / \
+ | N / \
+ |_______ / STROBE \
+ \DATA WORD/
+ \ =1 ?/
+ \ /
+ V Y
+ +------------+------------+
+ | LOAD SHIFT REGISTER |
+ | OUTREQST <-- 0 |
+ | COUNTER <-- 1 |
+ +-------------------------+
+ +---------->|
+ | V
+ | / \
+ | / \
+ |N / RFNBIT \
+ +----- \ = 1 /
+ \ ? / +----------+
+ \ / | | N
+ V Y | / \
+ +--------+--------+ V / \
+ | THERE'S YOUR |----------->/ RFNBIT \
+ | HOST BET <-- 1 | \ = 0 /
+ +-----------------+ \ ? /
+ \ /
+ | Y
+ +-+-+
+ | A |
+ +---+
+
+
+
+Wingfield [Page 4]
+
+RFC 12 IMP-HOST INTERFACE FLOW DIAGRAMS 26 August 1969
+
+
+ +---+
+ | A |
+ +---+
+ V
+ +--------------+-------------+
+ | THERE'S YOUR HOST BIT <--0 |
+ | BTAVL <-- 0 |
+ +----------------------------+
+ V
+ / \ / \
+ / WORD\ Y / \ Y
+ /LENGTH -1\---------->/ LSTWD \---+
+ \ = 1 / \ = 1 / |
+ \ ? / \ ? / |
+ \ / \ / |
+ | N | N |
+ V | |
+ / \ | |
+ / WORD\ | V
+ ________________ / LENGTH \ | +------------+
+ | \ = 1 / | | LIBIT <- 1 |
+ | \ ? / | +------------+
+ | \ / V |
+ | |<-----------------------<------+
+ | V
+ | +-----------------+
+ | | PUSH SHIFT REG. |
+ +-------------+ |INCREMENT COUNTER|
+ | LIBIT <-- 0 | +-----------------+
+ +-------------+ V
+ | +---+
+ | | B |
+ V +---+
+ / \
+ / \
+ / LSTWD \ Y +-------------+
+ \ = 1 /--------------------------->| END OF |
+ \ ? / | MESSAGE |
+ \ / +-------------+
+ | N
+ V
+ +---+
+ | C |
+ +---+
+
+
+ [ This RFC was put into machine readable form for entry ]
+ [ into the online RFC archives by Lorrie Shiota]
+
+
+
+Wingfield [Page 5]
+
+RFC 12 IMP-HOST INTERFACE FLOW DIAGRAMS 26 August 1969
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Wingfield [Page 6]
+