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MON 316B (octal) - SetRemoteAccess (SLRMO)

Switches COSMOS remote file access on and off. The COSMOS network lets a program open files on remote computers directly; when remote access is on and a file does not exist locally, the default remote system (set with MON 314B DefaultRemoteSystem) is searched. A single INTEGER2 Mode argument turns the feature off (0) or on (1). Only available with COSMOS installed. ND-100 call.

Status: byte-verified (dispatch + worker body). The worker is real carved code in 006-S3FS. All addresses/values are octal.

CORRECTED 2026-07-13. The previous version of this folder said the worker was misattributed / "not recoverable from these carved bytes", claiming GOTAB[316] = 112355B resolved to a DSI5 device/interrupt routine. That was an artefact of the wrong dispatch model. MON calls take their worker from MCTAB @ 005620B (segment 044-S3IDPIT), not from that GOTAB (which is MFELL for 224 of 256 calls). MCTAB[316B] = 027530B = SLRMO (byte-proven), and that worker IS carved in 006-S3FS. The DSI5 / "not recoverable" reading came from the disproven "uncarved CALLPROC bridge" story. See ../317B-ExecuteCommand/README.md and SINTRAN/CARVING-HANDOFF.md section 3a.

Dispatch path

flowchart LR
    A["User program<br/>MON 316B"] --> B["ENT14 level-14 entry<br/>026-S3IMPIT :072167B"]
    B --> C["GOTAB[316B] = MFELL<br/>MGOTA=071233B :071551B"]
    C --> D["MFELL level switch<br/>026-S3IMPIT :072114B -> CALLP 032201B"]
    D --> E["MCTAB[316B] = SLRMO<br/>MCTAB=005620B :006136B = 027530B"]
    E --> F["SLRMO worker<br/>006-S3FS :027530B"]
    class A blue
    class B,C,D,E teal
    class F green
    classDef blue fill:#E3F2FD,stroke:#0D47A1,color:#0D47A1
    classDef teal fill:#E0F7FA,stroke:#00838F,color:#00838F
    classDef green fill:#E8F5E9,stroke:#2E7D32,color:#2E7D32

There is no dashed hop. GOTAB[316B] = MFELL (byte-proven, 74 4c); MFELL is a program-level switch, not a subroutine call. The monitor level then indexes MCTAB and reaches SLRMO.

Code location (dispatch path)

Byte offset = (addr - loadbase) in octal words x 2 (decimal). Offsets reproduced with dd.

Role Segment Addr (octal) Byte offset Symbol Verdict
GOTAB[316B] slot 026-S3IMPIT.asm 071551B = 072114B 32466 -> MFELL VERIFIED
MCTAB[316B] slot 044-S3IDPIT.asm 006136B = 027530B 2236 -> SLRMO VERIFIED
SLRMO worker body 006-S3FS.asm 027530B-027541B 1712 SLRMO VERIFIED

Verify by hand (from tools/sintran-segment-carver/versions/L-VSX-500/segments/): 

dd if=026-S3IMPIT.bin bs=1 skip=32466 count=2 | od -An -tx1   ->  74 4c   (= 072114B = MFELL)
dd if=044-S3IDPIT.bin bs=1 skip=2236  count=2 | od -An -tx1   ->  2f 58   (= 027530B = SLRMO)
dd if=006-S3FS.bin    bs=1 skip=1712  count=2 | od -An -tx1   ->  ba 06   (= 135006B, SLRMO entry: JPL I 6)

Instruction walkthrough

Full listing: 316B-SetRemoteAccess.ASM.

SLRMO is a short routine (027530B-027541B) that flows into RSCAL (027542B).

Helper call + test (027530B-027532B). JPL I 6 (-> 027536B) calls a small helper that zeroes two locations (STZ -4 / STZ 4) and returns a state word; LDA 6 reloads it and JAZ 3 (-> 027535B) skips the store when it is zero (COSMOS not present / precondition not met).

Apply the Mode argument (027533B-027535B). On the active path, LDA ,B 12 loads the caller's Mode argument and STA I 4 writes it through the pointer at 4 into the resident remote-access flag; JMP I 4 (-> 027541B) returns. Setting Mode = 0 clears remote access, Mode = 1 enables it.

The helper call, the zero-test fork and the store-through-pointer of the Mode argument are byte-proven; the exact identity of the resident flag written is inferred from the call semantics and the sibling SDRUS/RSCAL context.

Parameter / register contract

Reg / field Dir Meaning Verdict
,B 12 (Mode) in 0 = remote access off, 1 = on; stored via STA I 4 VERIFIED (bytes); on/off meaning inferred (manual)
resident remote-access flag out target of STA I 4 (pointer at 4) VERIFIED (bytes); identity inferred
state word internal from helper 027536B; JAZ skips the store when zero VERIFIED (bytes)
return out JMP I 4 (-> 027541B) VERIFIED (bytes)
availability in COSMOS installed inferred (manual)

Pseudo-code (for an emulator)

See 316B-SetRemoteAccess.pseudo.c - the helper call, the zero-test fork and the store of the Mode argument are byte-verified; the identity of the resident flag is inferred.

Honest caveats

What is byte-proven: GOTAB[316B] = MFELL; MCTAB[316B] = 027530B = SLRMO; the SLRMO entry bytes at 027530B in 006-S3FS match the disassembly (135006B = JPL I 6); the worker calls a helper, forks on a zero test, and (on the active path) stores the caller's Mode argument through a resident pointer.

What is NOT proven: the exact identity of the resident remote-access flag written by STA I 4, the internals of the helper at 027536B, and the COSMOS-installed availability precondition (from the manual).

Correction to earlier work. The old folder read the disproven GOTAB, reported GOTAB[316] = 112355B -> DSI5, and concluded the worker was "not recoverable". The byte-proven worker is MCTAB[316B] = SLRMO = 027530B, real carved ND-100 code. The DSI5 / "not recoverable" reading was the wrong-overlay error.

Method: ../../../../../EXTRACTING-RESIDENT-CODE.md - master map: ../../MON-CALL-INDEX.md.