One of the usernames that the receptionist (p2,receptionist) knows about very early in a big bang is "SYSTOOL" (note upper case). This username leads to some keys which are powerful enough to do low level system debugging. See (admin).

Logging in to systool leads to a switcher {(p2,switcher)}.

Branch "a" of that switcher leads to a DDT {(p2,ddt)}. The domain under that DDT obeys the primordial program SYSTOOL. It also has the following keys (which can be manipulated by the DDT KEY command as well as by the domain):
Slot 0: A fetch key to the womb facilities node {(p3,wombfacil)}

Slot 4 (SYSNODE): a node key to a node known as "SYSNODE", which has:

Slot 0: a fetch key to a node (WOMBLIST) containing a domain key to each domain in the early womb.
Read "GNOSIS ASSEMBLE" and count "WOMB" macros starting from zero. The ith macro corresponds to slot i of this node.

Slots 10 and 11 have bnode keys for SNODE and SK1. Slot 14 of a bnode holds the builders key.

Slot 1: A node key to the privileged node, containing:
Slot 0: The GRCV Control key {(p2,grcv)}

Slot 1: The LUD {(lud)}. {a key to the record collection {(rc)} of usernames used by the receptionist and the keys to invoke for them. (The "Local User Directory".)}

Used for adding/deleting/changing users.

Slot 2: the Meter Monitor (p2,metmon)

Slot 3: An entry key to the kernel dump collector {(p2,cdump)}. See {(p3,cdump-today)} for how to look at dumps.

Slot 4: A CKERN key that copies the kernel to the primary IPL range {(p2,ckern)}.

Slot 5: TAPESYSNODE key only in No-Disk versions

Slot 6: The KIDC key (p2,kidc).

Slot 7: The Weakener (p2,weakener)

Slot 8: The TLA factory (p2,tlafact)

Slot 9: keysafe directory (keys to give to users)

Slot 10: an ADDLUDKY (p2,addlud) for the default LUD built by WOMBKEEPer..

Slot 11: A CKERN key that copies the kernel to the secondary IPL range {(p2,ckern)}.

Slot 12: an entry key to the dial-up lines receptionist, suitable for use as a type 2 LUD entry.

Slot 13: The kernel diagnosis key {(p2,kdiag)}

Slot 14: DOMERRORLOG for use by CKPTDVR (p3,derrorlog)

Slot 15: Extension for password encryptor

Slot 2: a node key to a node known as "PRIMORDSTUFF", which has:
Slot 0: a domain key to PSB2DOM.

Slot 1: a domain key to DCCDOM.

Slot 2: a domain key to DCCDCDOM.

Slot 3: a domain key to SBTDOM.

Slot 4: a domain key to SBTDCDOM.

Slot 3: The Checkpoint key {(p2,checkpoint)}.
Used for taking a checkpoint before bringing the system down.

Slot 4: A node key to the kernel node
{(kernel-logic,kernel-node)}

Slot 5: A domain key to the womb keeper.

General slot 2 of the WOMBKEEPER holds SWOMBLIST. See (p3,systool_use) about using this key.
SWOMBLIST is a supernode holding bnodes for early styles of objects. See (p3,primdir) for information on the use of SWOMBLIST.

General slot 2 of WOMBKEEPER holds SUPPFACIL supernode.

Slot 6: A node key to the sysnode extension (SYSNODEEX).
Slot 0: The device allocation key {(p2,bdevice)}.

Slot 1: A read-only page key to the primordial womb directory {(p3,primdir)}.

Slot 2: The kernel error wait key {(p2,kerrorwait)}.

Slot 3: BOOTSEG a segment key to a bootstrap command file

Slot 4: DEVALOC {(devaloc)}

Slot 5: RECEPF (p2,recepf)

Slot 6: VDKRC a record collection of Domain keys of primordial domains that have trapped.

Slot 7: the User.Sys. Directory as built by WOMBKEEPER

Slot 8 The Kernel IO measurement key.

Slot 9 a segment with a command file to format disks using GNFORM.

Slot 10: BWAIT(1)

Slot 11: CDAPEEK

Slot 12: KIWAIT

Slot 13: KERRORLOG key.

Slot 14: CONFIGF factory for early debugging

Slot 15: A node key to a node, SYSNODEX1 holding slots:

Slot 0: The CP message key {(diag8)}.

Slot 1: The kernel key to CP's IUCV function

Slot 2: The DIAGNOSE 4C key {(diag4c)}.

Slot 7: A fetch key to a node containing a domain key to each SIK2 simulator.

Slot 8: A node key to the prime meter.

Slot 9: A node key to another privileged node, containing:

Slot 2: The TYMLRECE key (p2,tymlrece).

Slot 13: A key to the standard factory creator WITH recall builder's rights

Slot 14: A key to a node holding keys to the banks held by objects created by WOMBKEEP. The WOMBKEEP listing is currently the definition of which of these banks are held by whom.

Slot 10: The peek key {(p2,peek)}.

Slot 11: The charge set tool key {(p2,cst)}.

Slot 12: A read-only segment key to the PL/I library.

Slot 13: A node key to a node {built by SYSTOOL} with:

Slot 3: The space bank from the womb

Slot 5: A spacebank limited to 50% of the space from INPUTSB

Slot 6: A spacebank limited to 90% of the space from INPUTSB

Slot 7: Shared mail directory with restricted rights

Slot 9: Record collection of usernodes for installed users

Slot 10: Shared mail directory

Slot 11: Write key to SYS.

Slot 14: Dump Directory

Slot 15: Domain key to domain under Peek DDT

Slot 14 (SYSNSWITCHER): a key to systool's switcher.

Slot 15: The Journalizer node which contains:

Slot 0: A R/O page key to the journal page {(p1,journal-page)}.

Slot 1: The Checkpoint key {(p2,checkpoint)}.

Slot 2: The Journalize Page key (journalize-page)

That switcher is also used for a Virtual Domain Keeper that is installed in WOMBFACILRESDOMKEEP {(p3,wombfacilresdomkeep)} after the receptionist is initialized. Therefore other branches may lead to DDT's over crashed domains.

Introducing new users.
When a new general user is introduced to the system several things are required of the system administrator. A zapper module {(p2,zm)} should be created and put in the LUD under the user's Tymnet name. A command language interpreter {(p2,cli)} should be presented with the SIK3 and SOK3 keys to the zapper module and the CCK3 key should be placed in a new directory {(rc)} and that directory given to the command language interpreter.

These are keys that are held by the program SYSTOOL. If you log in to SYSTOOL {(systool)} and talk to branch a (which will want to talk to you) you will be talking to a domain DDT over SYSTOOL. Subsequent to a big bang ";t0,b;u;w" must be typed to DDT. There are several subroutines in SYSTOOL which know where to get these keys. SYSTOOL is designed to be used by someone while reading a listing of SYSTOOL.

Kernel Dump Collector.

Recipe for looking at kernel crashes:
To look at a crash, arrange for a domain with a DDT over it, perhaps with commands such as "KC DOMCRE 0 (,,SPACEBANK) (,CRASH_DOM)" and "DEBUG CRASH_DOM". Put the dump key from the directory DUMP. in the domain thus: "KC CRASH_DOM 48 (,dump-key)". Then say to DDT "KERNSYMS;;" {(ddtdoc,0477)}.

The checkpoint driver CKPTDVR normally calls CDUMP whenever necessary.

CDUMP(0;->c;DD) will collect a Kernel dump if it has not yet been collected. c will be zero and DD will be an entry key to the record collection that holds the system dumps (the DUMP Directory). The name for each entry is generated from the date and time the dump was taken. The names are arranged in the record collection in order of time. If there are any obsolete temporary dumps they will be deleted and their names removed from the dump directory.

CDUMP(1;->c;DD) will collect a Kernel dump using a faster technique. Since the dump segment is a mapping of the dump range itself, subsequent dumps will destroy the dump. Dumps collected by this technique are call temporary dumps. Upon completion any previous temporary dumps will be deleted and their directory entries removed, c will be zero and DD will be an entry key to the record collection that holds the system dumps (the Dump Directory). The name for each entry is generated from the date and time the dump was taken with the string "#TEMP" appended. The names are arranged in the record collection in order of time.

CDUMP(kt;->X'E0D';)

Each entry in the Dump Directory has a key which obeys the following order codes:

DUMP(0 ==> 0;K) returns in K a read only segment that matches the kernel image at the time of the dump.

DUMP(1 ==> 0;K) returns in K a read only page key to the dump header, see {(kernel-logic,d-header)}.

DUMP(2 ==> 0;K) returns in K a key to the Space Bank used to create all the space for this copy of the dump.

DUMP(kt ==> 4;)

DUMP(kt+4 ==> ) destroys the dump.

Copy Kernel to IPL Range.
A CKERN key has one of the IPL ranges associated with it.

CKERN(0;SEG->0) will copy the image of the kernel in segment SEG to the IPL range. The first byte of the kernel is at location X'1000' in the segment and is expected to be KERNDEF, which holds the address of the last byte of the kernel in its first word.

CKERN(1; => 0;) IPL's the kernel in this range.

CKERN(kt==>X'40F0D'). See (ck) about access to CKERN.

CKERNC(0;PSB,M,SB,PRANGE => 0;CKERN) creates a CKERN key for the IPL range identified by the PRANGE key. This call uses the extended jump protocol.

CKERNC(kt==> X'60F0D')

Who is joined ?
The command "key node,diruserdk,,(31);;" will put a name sequenced RC in 31. This has an entry for each user who "has been joined" to the system. The key is an upper case ascii Tymnet user name.

The key of such a record is a node key to a node with the following layout:

SLOT 0: The user's directory

SLOT 1: The guard to the user's space bank

SLOT 2: A node key to the user's meter

SLOT 3: A domain key to the user's command interpreter.