Initdb and IpcMemoryCreate Errors

Hi,

System details:
Pentium III 850MHz w/128Mb RAM, 12Gb free disk.
Windows 2000 SP1
Cygipc v1.9

I have 2 problems with PostgreSQL 7.1-2 (precompiled) and Cygwin 1.1.8 (I
know the docs say don't use this version, however I can't find 1.1.7
anywhere) - I have upgraded to the 20010423 snapshot of cygwin1.dll. The
first problem (which I can work around) is with initdb which gives the
following output:

PC20 /data $ initdb
This database system will be initialized with username "administrator".
This user will own all the data files and must also own the server process.

Fixing permissions on existing directory /data
Creating directory /data/base
Creating directory /data/global
Creating directory /data/pg_xlog
Creating template1 database in /data/base/1
DEBUG: database system was shut down at 2001-04-25 13:35:03
DEBUG: CheckPoint record at (0, 8)
DEBUG: Redo record at (0, 8); Undo record at (0, 8); Shutdown TRUE
DEBUG: NextTransactionId: 514; NextOid: 16384
DEBUG: database system is in production state
Creating global relations in /data/global
DEBUG: database system was shut down at 2001-04-25 13:35:10
DEBUG: CheckPoint record at (0, 112)
DEBUG: Redo record at (0, 112); Undo record at (0, 0); Shutdown TRUE
DEBUG: NextTransactionId: 514; NextOid: 17199
DEBUG: database system is in production state
Initializing pg_shadow.
Enabling unlimited row width for system tables.
Creating system views.
Loading pg_description.
/usr/bin/initdb: cannot create /tmp/initdb.1468: permission denied
/usr/bin/initdb: cannot create /tmp/initdb.1468: permission denied
cat: /tmp/initdb.1468: Permission denied
Setting lastsysoid.
Vacuuming database.

initdb failed.
Removing temp file /tmp/initdb.1468.

I have found that modifying initdb to use "initdb.$$" instead of
"/tmp/initdb.$$" resolves this problem. I have checked permissions on /tmp
and that there are no existing files in there which may cause grief and all
appears OK.

The second problem occurs when I attempt to start the postmaster - I get the
following error:

PC20 /data $ postmaster -i &
[1] 1484
PC20 /data $ IpcMemoryCreate: shmget(key=5432001, size=1245184, 03600)
failed: Not enough memory

[1]+ Exit 1 postmaster -i

I have tried with cygipc running both as an NT service and from the command
line.

Any help would be greatfully received (future pgAdmin development depends on
it!! :-))

Regards, Dave.