








        UUnniixx//vv77mm RReelleeaassee 22..11 -- SSooffttwwaarree DDeessccrriippttiioonn

                        _F_r_e_d _C_a_n_t_e_r





     UNIX(R)  version  seven  modified, `Unix/v7m' is a full
source distribution of Unix version seven plus the  enhance-
ments  developed  by  the  Unix Systems Engineering group at
Digital.  The latest Western Electric  addenda  tape,  dated
12/2/80  is also included on the Unix/v7m distribution tape,
see  `/sys/addenda/README'  for  more  details   about   the
addenda.   The  documents  `Setting  up Unix', `Regenerating
System Software', and the accompanying manual  pages  super-
sede the equivalent standard Unix version documents.













     Digital  Equipment  Corporation  assumes  no  responsi-
bilites for this software and makes no warranties  or  guar-
anties as to its suitability or completeness.



























                             -2-


DDiissttrriibbuuttiioonn FFoorrmmaatt

     The  distribution  tape  is available at two densities,
800 BPI for use with the TU10/TE10 and TU16/TE16 tape drives
and  1600  BPI  for  use  with  the  TS11 and TU16/TE16 tape
drives.  The 1600 BPI tape can be  used  for  the  TU16/TE16
only  if  the TM03 tape controller (WITH AUTO DENSITY SELECT
ENABLED) is used, the 1600 BPI tape cannot be used with  the
TM02 tape controller.

     The  distribution  tape  consists  of  some preliminary
bootstrapping programs followed by a root file system  image
in dump/restor format, the system sources in tar format, and
a tar formatted user file system with the remainder  of  the
sources.

     The system as distributed contains binary images of the
system and all the user level programs,  along  with  source
and  manual  sections for them--about 2100 files altogether.
The binary images, along with other things needed  to  flesh
out  the  file system enough so UNIX will run, are to be put
on one file system called the `root file system'.  The  file
system size required is 9600 blocks.  The second file system
contains the system sources,  needed  to  rebuild  Unix  and
requires  about 5000 512-byte blocks.  The third file system
has the remainder of the sources and all of  the  documenta-
tion, it requires 20,000 blocks of storage.

UUnniixx//vv77mm VVeerrssiioonnss

     The  Unix/v7m  tape includes three versions of the Unix
operating system; `unix_id', the separated  Instruction  and
Data  space  version  for  use  with the PDP11/44, PDP11/45,
PDP11/55, and PDP11/70 processors;  `unix_ov',  the  overlay
text kernel used with the non-separated Instruction and Data
space processors, PDP11/23,  PDP11/24,  PDP11/34,  PDP11/40,
and PDP11/60; `unix_i', the preconfigured unix monitors used
only for the initial loading of Unix from  the  distribution
tape.

     The  separated  I and D space version takes full advan-
tage of the features in Unix version seven and  can  support
up  to  32 users, depending on the processor type and system
configuration.  The overlay text kernel is designed to  sup-
port about 10 users, more or less depending on the processor
and system configuration.  The overlay  version  limits  the
size  of  user  processes to 64 kb, due to the lack of sepa-
rated I and D space in the processor.

     The overlay unix kernel used in this  distribution  was
supplied  by Mr. Bill Shannon, thanks to Bill for a job well
done !











                             -3-


HHaarrddwwaarree RReeqquuiirreemmeennttss

     Unix/v7m, with the exceptions listed below, can be used
on any system that is configured with a processor, one disk,
and a tape from the following equipment list:


     CPU       DISK      TAPE
     ---       ----      ----

     PDP11/23  RL01/2         TU10
     PDP11/24  RK06/7         TE10
     PDP11/34  RM02/3         TS11
     PDP11/40  RP03      TU16
     PDP11/44  RP04/5/6  TE16
     PDP11/45
     PDP11/55
     PDP11/60
     PDP11/70


              OPTIONAL EQUIPMENT

     DISKS     TAPES     PRINTERS  COMMUNICATIONS
     -----     -----     --------  --------------

     ML11 TS03 LP11      DH11
     RS03/4    TU56           DM11 (DH modem control)
     RX02                DZ11
     RK05                DN11
     RF11                DU11
                         DL11
                         DC11






























                             -4-


1.   The processor must be equiped with a KW11-L line  clock
     or a KW11-P programmable clock.

2.   The `practical' minimum memory size for Unix/v7m on all
     processors is 256 K bytes.  A  memory  size  of  192  K
     bytes  is  acceptable, however the number of users will
     be limited.  Unix/v7m is NOT guaranteed  to  work  with
     less  than  192  K  bytes of main memory. In fact, on a
     PDP11/23 with 128 k bytes of memory it did not function
     properly.  For the most part it worked, but some impor-
     tant things, such as the floating point  simulator  (cc
     -f)  and  commands  that  used  floation point, such as
     iostat(1), did not work.  Also, the secondary bootstrap
     program  `boot'  will not function with less than 192 K
     bytes.

3.   All of the FP11 type floating point processors are sup-
     ported by Unix/v7m.  The PDP11/40 Float Instruction Set
     is not supported by Unix.  A floating  point  simulator
     is available for processors which are not equipted with
     floating point hardware. However this code is very slow
     and  if  any  serious floating point work is to be done
     the floating point hardware is required.

4.   Four RL01 disk packs are required to contain this  dis-
     tribution,  however, Unix/v7m can be operated on as few
     as two RL01 drives, three are recommended.

5.   With the RL02 and RK06 disks two drives are required.

6.   The RK05 disk is not large  enough  to  be  the  system
     (root) device, it is supported as a user device only.































                             -5-


7.   The  RM03  disk can only be used with the PDP11/70, all
     other processors must use the RM02.

8.   The RX02 can be  used  in  single  and  double  density
     modes, the RX01 is not supported.

9.   The  ML11 solid state disk may be connected to the same
     massbus with the system disk or on a separate  RH11  or
     RH70 massbus disk controller.

10.  The RS03/4 and the ML11 are mutually exclusive.

11.  The  TS03  tape  is  supported  as  a user device only,
     because it cannot accept reels of tape that are greater
     than 600 feet in length.

12.  For  the TS11 a single drive only is supported.  A TS11
     and a TM11 (TU10/TE10) may be configured  on  the  same
     system, with certain restrictions.  The TM11 controller
     must be at CSR address 172520 and vector  224  and  the
     TS11  must  be  at  address 172550 and vector 260.  The
     TS11 can be booted as `MS6', assuming that  the  system
     is equiped with a M9312 ROM bootstrap using the console
     emulator.  Unix/v7m will automatically  adapt  to  this
     configuration,  the  TM11 will be accessed by `mt0' and
     the TS11 by `mt1'.  The `Setting up Unix' document  has
     instructions  , flaged by `tstm', which pertain to this
     configuration.  If the TS11 is the  only  tape  on  the
     system it must be at CSR address 172520 and vector 224.

13.  An additional RH massbus disk controller, with a combi-
     nation  of  RM02/3,  and/or RP04/5/6 disks attached, is
     also supported.  This configuration is referred  to  in
     `Setting  up Unix' as the `hm' disk.  There is no hard-
     ware boot ROM available to bootstrap from a disk on the
     second  RH  controller,  however,  it  can be booted by
     calling into memory a copy of `boot' from another  disk
     or the distribution tape.

























                             -6-


PPDDPP1111//2233 AAnnoommaalliieess

     There  are  certain  unexplained error conditions which
cause the PDP11/23 to enter  a  state  where  it  cannot  be
rebooted  without  powering  the system off and then back on
again.  When the PDP11/23 is  booted  it  halts  instead  of
starting  the  primary bootstrap program, type `0g' to start
the primary bootstrap.

AA WWoorrdd AAbboouutt DDiisskk MMeeddiiaa

     Unix expects the disk media on which  it  lives  to  be
perfect,  i.e.,  no  bad blocks. The Unix file system places
things (super block, i list, free list) in  fixed  positions
on  the  disk,  there  is no strategy for mapping around bad
blocks. The Unix device drivers for disks with error correc-
ton capability (hp & hk) implement ECC in both block and raw
I/O modes.  All other disk  drivers  depend  on  retries  as
their only means of error recovery.  A bad disk block is one
that contains an error which cannot be  corrected  via  ECC,
for  disks  with ECC, or any error which cannot be recovered
via retry, for disks without ECC. Retry and ECC  recoverable
errors  are  "soft"  errors.  Certain disk packs (RM02/3 and
RK06/7) have the bad blocks flagged in  the  sector  header.
The  disk  hardware  will not attempt to write or read these
blocks, but instead will report a bad sector error (BSE).

To qualify a disk pack for use with Unix,  First,  obtain  a
list  of  the locations of all bad blocks and soft errors on
the disk pack. The DEC format and verify  diagnostic  should
provide  this  information  when the disk pack is formatted.
Compare the error location list to the  file  system  layout
for  the  type of disk to be used, the following guide lines
should be used:

1.   The root file system must be free  of  bad  blocks  and
     although  soft  errors  can be corrected they should be
     avoided if possible.  Soft errors can not be  tolerated
     in any disk block that is allocated to the file "/unix"
     or any other  bootable  file,  because  the  standalone
     bootstrap does not implement ECC.

2.   The  swap area must be free of bad blocks.  Soft errors
     should  be  avoided  if  possible,  because  the   time
     required  to  correct  them will degrade system perfor-
     mance.

3.   The user file systems must be free of bad blocks,  soft
     errors  are  generally not a problem in the user areas.
     It is sometimes possible to use a disk  pack  with  bad
     blocks in the user file systems by rearranging the disk
     partitions to avoid the bad blocks.











                             -7-


RReelleeaassee nnootteess

     The following notes give a very  brief  description  of
the  differences  between  this  distribution  and  Unix/v7m
release one.  The release notes are attention getters  only,
refer  to  the  documentation  for more detailed information
about the changes and new features.

1.   The `#' prompt has been added to the  block  zero  disk
     bootstraps, see boot(8).

2.   The  overlay  Unix  kernel  must be booted with the two
     stage bootstrap, see boot(8).

3.   The RK06 and RK07 block zero disk  boot  programs  have
     been combined into `hkuboot'.

4.   The  block  zero  disk  bootstraps would halt if only a
     return was typed, they  will  now  return  to  the  `#'
     prompt.

5.   The old (unix_i) I space only Unix systems may still be
     booted directly, without using the two stage bootstrap.

6.   The  `-p'  option  has been added to the ls(1) command,
     see ls(1).

7.   Logins may now be disabled/enabled at the console  ter-
     minal, see logins(1m).

8.   There  is now system shutdown command, see shutdown(8).

9.   The iostat(1m) command has been  completely  rewritten,
     see iostat(1m).

10.  The fsck(1m) command was added, see fsck(1m).

11.  The  ps(1) and pstat(1m) commands no longer rely on the
     param.h file for  system  parameter  information,  they
     read  it  from  the  unix  kernel  directly,  using the
     namelist and /dev/mem facilities.

12.  Several other commands have been changed, see the docu-
     mentation for the details.

13.  The file `/sys/addenda/README' is must reading !

















                             -8-


14.  New  processors  and  disks are supported, see hardware
     requirements above.

15.  Local terminals are now supported , see ttys(5).

16.  The init(8) program has been  modified  to  reread  the
     ttys file, see init(8).

17.  Many  floating  point  changes  have been made, see the
     documentation for more detail.

18.  A TS11 and A TM11 magtape on the  same  system  is  now
     supported.

19.  Several bugs in the core dump code were fixed.  The new
     core dump starting address is now 1000 instead of 44.

20.  The RK06/7 disk driver has  been  completely  rewritten
     and the Rl01/2 driver has been improved.

21.  The RM02/3, ML11, and RP04/5/6 disks on the second RH11
     or RH70 are now supported, see hm(4).

22.  The HP and HK disk drivers now have full ECC  in  block
     and raw I/O modes.

23.  Memory parity error handling has been improved.

24.  Stray vector handling has been improved.

25.  Disk  free  list  spacing  has  been optimized for disk
     rotation.

26.  The `mkconf' program has been extensively modified, see
     mkconf(1m).

























