Every protocol the FujiNet N: device speaks — file servers, web services, sockets, shells, mail, and calendars — with the complete devicespec grammar, every value and error code, and worked examples for each. With chapters for Atari BASIC, Applesoft BASIC, ADAM SmartBASIC, C with fujinet-lib, IntyBASIC, and FujiNet NOS.

This is the GitHub-wiki edition of the print handbook (fujinet-network-protocol-handbook.pdf). The two are kept in sync by hand. Every scheme string, aux value, command byte, constant, and error code is transcribed from the live sources: fujinet-firmware lib/network-protocol (commits c026d9a12 + 07e53c764, Sep 2026), fujinet-lib v4.11.2, fujinet-nhandler, smartbasic-1.x, and the programmer's guides in fujinet-manuals.

• Part I — The Network Device Model: Introduction · The devicespec · Open modes and translation · Channel modes · Status and errors · Special commands
• Part II — Filesystem Protocols: The filesystem model · TNFS · SD · SMB · NFS · FTP · SFTP · HTTP and HTTPS · S3 · GDRIVE · ONEDRIVE
• Part III — Stream Protocols: TCP · UDP · TELNET · SSH · WS and WSS
• Part IV — Session Utilities: SSH.KEYGEN · SSH.COPYID · CLIPBOARD · CPM · TEST
• Part V — Mail and Calendar: The mailbox model · GMAIL · IMAPS · The calendar model · GCAL · ICAL / WEBCAL / ICALH
• Part VI — From Your Machine: Atari BASIC · Applesoft BASIC · ADAM SmartBASIC 1.x · C with fujinet-lib · IntyBASIC · NOS
• Appendices: Capability matrix · Scheme quick reference · Implementation notes · The programmer's guides

To your computer, the FujiNet's network device is one more peripheral: open it with a name, read and write like a file, close it. The name is a devicespec:

N:HTTPS://fujinet.online/hello.txt

Everything before the first colon addresses a device on your machine's bus; everything after is a URL whose scheme selects a protocol adapter in the firmware — 25 adapters answering to 28 scheme strings.

Every protocol is driven by the same four beats:

1. Open — devicespec + access mode (aux1) + translation mode (aux2).
2. Status — bytes waiting, connection state, error code.
3. Read / write — move bytes.
4. Close — flush, tear down, free.

The adapter lives in the FujiNet, not your computer: the ESP32 (or fujinet-pc) holds the buffers, speaks TLS, parses JSON, walks OAuth. An 8 KB machine reads Gmail because the hard part happens across the bus.

Schemes are uppercased before matching. An unknown scheme fails the open with error 144; an unparseable URL with 165.

N[unit]:SCHEME://user:password@host:port/path?query

• N1:–N8: select independent channels (bare N: = N1:); how many you get is a bus property (Atari 8, Apple/ADAM extensions expose 1–15, Intellivision devices $71–$78).
• Credentials reach a protocol three ways: in the URL; via the username ($FD) / password ($FE) specials before the open; or from stored config (OAuth tokens, S3 keys) so nothing secret crosses the vintage bus.
• Pitfall: the firmware only hands stashed credentials over when the username is non-empty. A password alone never arrives.

aux1 (access mode): 4 read · 6 directory (7 alt) · 8 write · 9 append · 12 read/write · 5/13/14 HTTP-specific (DELETE / POST / PUT-with-headers).

aux2 (translation): what a line ending looks like on the network side; the FujiNet folds it to/from your machine's native EOL.

Use mode 0 for anything binary. The Atari also maps BEL/BS/TAB to ATASCII equivalents. A sticky translation ($54 special) is OR-ed into later opens — except directory opens, where aux2 means a format or width. Generated text (directories, indexes, status reports) arrives with the platform line ending already applied and translation off.

The $FC special sets the channel mode: 0 protocol (default), 1 JSON, 2 SGML. The JSON three-beat, identical on every platform:

1. Open the URL, set channel mode JSON ($FC aux2=1).
2. Parse ($50 'P') — the FujiNet builds the document tree.
3. Query ($51 'Q') — send a path like /results/0/name; read the value back.

$FB tunes result translation (aux1=0) and the result line-ending byte (aux1=1). JSON/SGML live in lib/fnjson / lib/fnsgml, driven by the bus device — which is why any protocol can carry them. Do not confuse $FC (channel mode) with $4D (HTTP body/header channel, HTTP only).

Status returns 4 bytes on every bus: avail (u16 LE, capped 65534), connected, error. The idiomatic loop: status until avail > 0 (or connected drops), read, repeat until error 136. Some adapters do their first real work at the first status (HTTP fires its request there). A failed open destroys the adapter, but the error is latched for the next status. On buses with an interrupt line, a timer polls channels and asserts it when data waits or the connection drops ($5A sets the rate).

Printable command bytes match their mnemonic; on the Atari the XIO number is the command byte.

The filesystem specials are one-shot: a fresh adapter is built from the devicespec in the payload, does the op, and is destroyed — they work with no open channel, and need a complete devicespec every time.

All ten adapters derive from NetworkProtocolFS. File opens resolve the path (with crunched-8.3 recovery for long filenames), reads count fileSize down to error 136, seek/tell work where the backend allows. Directory opens (aux1=6) use aux2 as a format selector:

Wildcards * ? filter listings (*.*, **, - normalize to *); Atari builds append 999+FREE SECTORS except in RAW. Rename carries both names comma-separated: N:TNFS://host/path/OLD,NEW (no comma → 165). Some adapters advertise but stub operations — accepted, "success," nothing happens; see the capability matrix.

N:TNFS://host[:port]/path — port 16384, anonymous, plain UDP. The most complete citizen: all modes, all specials, real seek, and the only adapter returning real modified and created timestamps. Errors: not found → 170, read-only/denied → 167, no space → 162, EOF → 136, exists → 151, mount timeout → 138, else 144. Treat as LAN/public-archive transport — nothing is encrypted.

N:SD:/path — the FujiNet's own card; no host, no network. All modes; rename/delete/mkdir/rmdir real; lock/unlock honestly report 146; seek real. No card mounted → 200 on everything. Errno map: ENOENT → 170, EEXIST → 151, EACCES → 167, ENOSPC → 162, ENOMEM → 255.

N:SMB://[user:pass@]server/share/path — SMB2 via libsmb2, signing enabled. First path component is the share. Credentials from URL, else the $FD/$FE specials. A username/password with no lowercase at all is lowercased (friendly to all-caps machines; hostile to all-caps passwords). mkdir/rmdir/seek real; rename/delete/lock/unlock are silent stubs. Every library failure reports 144 — check server, share, credentials in that order.

N:NFS://host[:port]/export/path — NFSv3 via libnfs; a URL port sets both mount and NFS ports. Credentials are numeric: username special = UID, password = GID. Auto-negotiates the export boundary (tries the path's dir, falls back to the root export). mkdir/rmdir/seek real; rename/delete/lock/unlock stubs; errors collapse to 144.

N:FTP://host[:port]/path — always anonymous (anonymous/[email protected]); URL credentials ignored; no TLS. Read = RETR, write = STOR; append/read-write → 146. All six filesystem specials are silent stubs. Reply map: 226 → 136 (EOF), 421 → 210, 430 → 212, 45x → 167, 550 → 170, other 4xx/5xx → 144.

N:SFTP://user[:pass]@host[:port]/path — port 22. Password in URL = password auth; none = key auth with /.ssh/id_ed25519 from the SD card (see SSH.KEYGEN / SSH.COPYID). Full operation set, all real: seek, rename, delete, mkdir 755, rmdir, lock chmod 444 / unlock 644. EOF zero-pads reads. Errors: EOF → 136, no file/path → 170, permission/write-protect → 167, exists → 151, missing user/empty pass → 212, else 144. Host keys are not verified — safe from eavesdroppers, not from an active MITM.

N:HTTPS://[user:pass@]host[:port]/path?query — the biggest adapter: REST client, form poster, WebDAV filesystem.

The lazy transaction: open does not send the request — the first status does. Between them you may stage request headers and POST data. HTTP errors surface in that first status.

aux1 = method: 4 GET (path encoded) · 12 GET verbatim+headers · 8 PUT · 13 POST · 14 PUT-with-headers (sent as POST) · 5 DELETE · 9 DELETE+headers · 6 WebDAV PROPFIND directory.

$4D HTTP channel modes: 0 body · 1 collect headers (write names before the transaction; GET modes only) · 2 get headers (read values back) · 3 set headers (write Name: value) · 4 set POST data.

WebDAV: directory listings via depth-1 PROPFIND (falling back to plain GET on 405/408); rename = MOVE, delete = DELETE, mkdir = MKCOL, rmdir = delete.

Seek: on a GET body channel, $25 re-issues with Range: bytes=n-; a 200 (Range ignored) is handled by skipping.

Status map: 2xx → 1 · 401/402/403/407 → 212 · 404/410 → 170 · 405 → 146 · 408 → 138 · 423/451 → 167 · other 4xx → 214 · 5xx → 215 · connect failure → 207.

S3://[KEY:SECRET@]endpoint[:port]/bucket/key?region=..&tls=0|1 — AWS Signature V4 signed inside the FujiNet; works with MinIO, Wasabi, Ceph. Credentials/region/TLS fall back to web-UI config. Reads stream GET; writes buffer and go out as one PUT at close (512 KB cap → 162); append downloads first; directories via ListObjectsV2 (paginated); mkdir = zero-byte folder marker; rename = copy+delete. No seek. Map: 2xx → 1, 403 → 167, 404 → 170, 409 → 151, no response → 207, else 144.

GDRIVE:///path/to/file — OAuth once in the web UI (shared grant with GMAIL/GCAL; token refresh via the FujiNet relay, client secret never on device). Paths resolve component-by-component to file IDs; shortcuts followed; trash invisible. Writes buffer (64 KB) and upload multipart at close; append pre-downloads. Directory format 130 appends Drive file IDs. Delete/mkdir real; rmdir = delete (removes non-empty folders!); no rename. Mount failure (207) means re-authorize.

ONEDRIVE:///path/to/file — Microsoft Graph, by path (no ID walk). Same buffered-upload model (64 KB PUT at close). Delete, mkdir (conflict → 151), rmdir = delete, and — unlike GDRIVE — real rename via PATCH. OAuth via the same relay pattern, [OneDrive] config.

Server mode: status connected=1 means a client is waiting; accept with $41; drop with $63 and it listens again (one client at a time). Errors: refused → 200, short read/write → 202, reset → 204, write with no client → 207, accept with no server → 208, nobody waiting → 209. Quirk: $63 reports an error even on success — trust the next status.

N:UDP://host:port/ (talk) or N:UDP://:port/ (listen) — the port is mandatory. connected is always 1. $44 retargets writes (N:host:port payload); $72 reports the last sender (fujinet-pc only); and the destination auto-learns the last sender, so read-then-write answers whoever spoke. Write with no destination → 207. Multicast join is not implemented.

N:TELNET://host[:port]/?term=ansi&cols=40&rows=24 — TCP plus a real Telnet state machine; negotiations answered invisibly (refuses ECHO, offers TTYPE, declines COMPRESS2/MSSP). term defaults dumb; NAWS is mentioned only if both cols and rows are given. Client only.

N:SSH://user[:pass]@host[:port]/?term=vanilla&cols=80&rows=24 — an interactive shell with a real PTY. Password in URL = password auth; none = key auth (/.ssh/id_ed25519). Missing username → 212 immediately. Status 136 when the remote shell exits. Auth rejected → 167. Host key logged, not verified. Password rides in the devicespec — prefer key auth.

N:WSS://host[:port]/path?frame=text — WebSocket client; WSS is WS over TLS. ?frame=text sends TEXT frames (default binary). Handshake gets 10 s → 200 on failure. One write = one frame. Peer close → 136; stalled transfer → 202; write after drop → 207.

N:SSH.KEYGEN://ed25519/ (add ?overwrite=1 — exact literal — to replace). Generates /.ssh/id_ed25519 + .pub on the SD card; refuses to touch an existing key otherwise; overwrite writes tmp files and renames. Read the report:

OK SSH.KEYGEN / TYPE ed25519 / OVERWRITE 0 / PRIVATE ... / PUBLIC ...

Failures are one-line SSH.KEYGEN error: ... reports with status 144.

N:SSH.COPYID://user:pass@host[:port]/ — password required (that's the point). Appends the public key to the server's authorized_keys (creating dir/file with right permissions, skipping if present). Report: OK SSH.COPYID / HOST / USER / KEY / STATUS installed|already-present. After keygen + copyid, password-less SSH://user@host and SFTP://user@host just work.

N:CLIPBOARD:///[0-9] — index 0 is the clipboard (shared with the web UI), 1–9 the history, newest first. Only 0 writable (else 167); unfilled slot → 170; 64 KB cap → 162; ?binary=1 stores verbatim forever. Text is stored LF-terminated; translation applies at close (commit). Pitfall: a write-mode open commits at close even if nothing was written — mode 8 + close empties the clipboard. Short reads NUL-pad and report 136.

N:CPM:// — boots RunCPM (CP/M 2.2 + CCP) inside the FujiNet; the channel is its console. Drives live on the SD card. Warm boots handled invisibly; session end → 136; empty console poll → 202; close halts the machine.

N:TEST://anything/ — returns one fixed line (This is test data…) terminated per your aux2; writes are hex-dumped to the debug log before and after translation. The loopback for plumbing tests, the microscope for translation bugs, and the official skeleton (Test.h/.cpp) for writing a new adapter.

Shared by GMAIL and IMAPS. Append/read-write → 135; write (mode 8) works only on providers that can send — GMAIL yes, IMAPS no (135).

?range=START-END (0-based, default first 20, max 200) and ?newest=0|1 page the index. For index opens aux2 = 255 yields packed records; any other value is a human listing at width = aux2 & 127 (0 → platform default: Atari 38, Apple 40, ADAM/CoCo 32, RS-232 80). Human index: two lines per message, sized to wrap perfectly at 40 columns. Packed records (little-endian, NUL-padded): MailIndexItem = msgNum u32, displayName[32], emailAddress[48], subject[128], timestamp u64 (220 bytes); MailAttachmentItem = attachmentNum u8, displayName[128], fileName[128], mimeType[48], length u64 (313 bytes). Everything is staged at open; reads drain to 136.

Writing a message: open mode 8 starts a draft; write RFC822-style header lines — KEY: value, colon required, keys case-insensitive — then a blank line, then the body verbatim; close sends:

TO: [email protected]
SUBJECT: Hello from an Atari

Sent from my 130XE over FujiNet.

Only TO, CC, BCC, SUBJECT (no FROM — the sender is the authenticated account). TO/CC/BCC accumulate on repeat; SUBJECT is last-wins. Any EOL works (0x9B/CR/LF/CRLF, mixed); aux2 translation is never applied to a write channel. Replies (mode 8 on /FOLDER/N) default an omitted TO to the original's Reply-To/From and an omitted SUBJECT to Re: (never doubled); the shortest legal reply is a blank line and a sentence; the target is pinned at open (bad N → 170). Verdict in the post-close status: 1 sent, 132 rejected draft (reason in debug log only), 162 oversized (16 KB, nothing sent); writing nothing = clean abort. Sent mail is text/plain UTF-8, no attachments; reading a write channel → 131. Sending is the only write — nothing is marked read, moved, or deleted. (The post-close verdict is latched on SIO/AdamNet/DriveWire/RS-232; other buses don't latch it yet.)

GMAIL:///Inbox[/N[/A]] — folders are Gmail labels (case-insensitive). Message 1 = oldest; newest = the count — so "latest" is read /Inbox, then open /Inbox/<count>. Bodies prefer text/plain. Uses the shared Google grant (scopes gmail.readonly + gmail.send). Map: 401 → 212 (re-authorize), 403 → 167 (scope missing), 404 → 170, silent/5xx → 210.

Sending (newest firmware): mode 8 on / composes, on /Inbox/N replies — the mailbox draft grammar above. Gmail stamps From/date from the account and files a copy under Sent; replies thread via the original's threadId + Message-ID/References (override the Re: subject and Gmail may display the reply outside the conversation). Needs the gmail.send scope — an older grant keeps reading but fails its first send with 167; re-authorize in the web UI. Reading still marks, moves, and deletes nothing.

IMAPS://user:pass@host[:993]/FOLDER[/N[/A]] — any IMAP server, implicit TLS (no STARTTLS). N = IMAP sequence number (1 = oldest). The most fine-grained login diagnostics in the book: no host → 165, no user → 212, TLS fail → 200, silent server → 202, odd greeting → 210, LOGIN rejected → 212, missing folder/message → 170, parse/fetch → 144. No sending: a mode-8 open is refused with 135 (compose is GMAIL-only).

Shared by GCAL and ICAL:

SCHEME://selector/VIEW[/DATE[/N]]

VIEW = DAY | WEEK | MONTH | AGENDA (scanned from the path's end); DATE = YYYY-MM-DD (or YYYY-MM for MONTH), default today; N = 1-based event in the view. aux1: 6 index · 4 count (or detail with N) · 8 compose (on /sel) or edit (on /sel/VIEW/DATE/N), providers permitting. Params: ?category= filter, ?count= (AGENDA cap, 20), ?days= (horizon, 365), ?wkst=MO, ?tz=, plus ?view=/date=/n= escape hatches. Windows are DST-correct; recurring events expand into occurrences; numbering is deterministic (sorted by start) and a 2-minute cache makes index-then-detail one fetch. aux2 = width/255-raw for indexes (as Mailbox), ignored for details. Packed record CalEventItem = eventNum u32, start u64, end u64 (exclusive, UTC), flags u8 (1 all-day, 2 recurring), summary[96], location[64], category[32], uid[64] — 277 bytes; CalListItem = name[64], category[32], id[128].

Writing: open mode 8, write field lines (KEY: value — the colon is required), close commits:

SUMMARY: Dentist
START: 2026-09-03 14:30
END: 2026-09-03 15:15
LOCATION: 12 Main St.
DESCRIPTION: bring the x-rays
CATEGORY: health

Six keys only: SUMMARY, START, END, LOCATION, DESCRIPTION (repeats to build paragraphs), CATEGORY. Blank lines are skipped (no header/body divide, unlike mail); any EOL works; aux2 translation never applies to a write channel. Times: YYYY-MM-DD (date-only = all-day) or YYYY-MM-DD HH:MM[:SS] — a T may replace the space, compact YYYYMMDD[THHMMSS] works, and a trailing Z/±HH:MM makes it absolute; otherwise it resolves in ?tz= (default the FujiNet's zone). Compose needs SUMMARY + START (missing END = +1 hour, or +1 day all-day; all-day END is inclusive). Edits change only sent fields: neither START nor END = times untouched; lone START keeps duration (unless it switches all-day↔timed, then compose defaults apply); lone END must match the event's form. Rejections all report 132 (unknown key, missing colon, bad time, missing required field, END ≤ START, mixed date forms — reason in debug log only). Verdict in the post-close status: 1 ok, 132 rejected, 162 oversized (16 KB), 170 target gone (resolved at open); writing nothing = clean abort. No delete. A successful commit drops the 2-minute listing cache, so re-list before editing again. (Verdict latched on SIO/AdamNet/DriveWire/RS-232 only.)

GCAL:///[sel]/VIEW[/DATE[/N]] — selector = calendar name → id → verbatim; empty = your "shown" calendars merged; * = everything (max 8). Categories: explicit (extended property) → Google color name → calendar name. Same Google grant; needs calendar.readonly (+calendar.events to write) — a grant never gains scopes retroactively; re-authorize in the web UI (scope problems → 167). Compose to / = primary; * refused (165). A calendar literally named Day/Week/Month/Agenda can't be compose-targeted by name (the view scan claims that segment) — use its id. Written CATEGORY round-trips via private extended properties. Edits go up as a PATCH and translate between Google's two date forms, so sending START in the other form switches all-day↔timed. Indexes expand recurrences, so editing N touches that occurrence only, never the series. Unparseable JSON → 213.

ICAL://feed-host/feed-path.ics/VIEW[/DATE[/N]] — any published .ics feed; WEBCAL = same over https (paste subscription links unchanged); ICALH = plain http. The feed URL is resent verbatim (secret URLs survive). Streaming parse: window-sized memory, recurrence expansion in-window, RECURRENCE-ID overrides patched at end of feed. No calendar list (/ → 165); read-only (135); detail is a second pass with the window widened a day each side. Compressed responses are refused (146). TZID-named times resolve in your configured zone — ?tz= overrides.

Load the NDEV handler (AUTORUN.SYS/NDEV.COM). Then:

10 OPEN #1,4,0,"N:HTTPS://FUJINET.ONLINE/HELLO.TXT"
20 STATUS #1,A:BW=PEEK(746)+PEEK(747)*256
30 IF BW=0 AND PEEK(748)=1 THEN 20
40 TRAP 80:FOR I=1 TO BW:GET #1,C:? CHR$(C);:NEXT I:GOTO 20
80 CLOSE #1

DVSTAT: bytes waiting PEEK(746)+PEEK(747)*256, connection PEEK(748), error PEEK(749). The XIO number is the command byte — the specials table above doubles as the XIO reference. XIO 15 flushes locally. JSON:

30 XIO 252,#1,0,1,"N:" : XIO 80,#1,0,0,"N:"
50 XIO 81,#1,0,0,"N:/status/message" : INPUT #1,V$

Edges: reads cap at 127 bytes/call; the DOS 2 menu unloads the handler; NDEV cannot reach the Fuji device; $4D reports 146. → FujiNet Programming Guide for the Atari (atari/programmers_guide/).

BRUN FUJINET hooks BASIC.SYSTEM's external commands (deliberately not & — the tokenizer mangles N-words). Eighteen commands, typed at ] or via PRINT CHR$(4);"…": NOPEN/NCLOSE/NSTATUS/NREAD/NWRITE, NJSONPARSE/ NJSONQUERY, NCD/NCAT/NCATALOG/NMKDIR/NRMDIR/NDEL/NTYPE, NLOAD/NSAVE, NTRANS/NACCEPT/NLOGIN/NHTTPMODE. Channels 1–15; translation 4 = PETSCII; errors via ONERR + PEEK(222).

 10 D$ = CHR$(4): Q$ = CHR$(34)
 30 PRINT D$;"NOPEN 1,";Q$;"N:HTTPS://ICANHAZIP.COM/";Q$;",4,0"
 40 PRINT D$;"NSTATUS 1,BW,CN,ER"
 50 IF BW = 0 AND CN = 1 THEN 40
 70 PRINT D$;"NREAD 1,A$,BW": PRINT "MY IP IS ";A$
 90 PRINT D$;"NCLOSE 1"

→ FujiNet BASIC Extension for the Apple II (apple2/basic_extension/) and the Apple II programmer's guide.

Seventeen native statements patched into the interpreter itself: same vocabulary as the Apple II (with NDIR), channels 1–15 → EOS devices 9+. Network failures raise BASIC error 37 (?Network Error n), ONERR-catchable; codes 1/136 never raise; no FujiNet → ?ILLEGAL QUANTITY ERROR fast.

220 ONERR GOTO 900
300 NOPEN 1,"N:HTTP://api.open-notify.org/iss-now.json",4,0
310 NJSONPARSE 1
320 NJSONQUERY 1,"/iss_position/latitude",lat$
340 NCLOSE 1
900 NSTATUS 1,bw,conn,err : PRINT "Network Error: ";err

AdamNet moves ≤ 1024 bytes per bus transaction. → the smartbasic-1.x repository's appendix, and adam/programmers_guide/ for EOS/Z80.

One portable API (cc65/z88dk/CMOC…): network_init/open/close, network_read/_read_nb (→ bytes or −error; EOF = −136), network_write, network_status, network_json_parse/query, the network_http_* family, network_fs_* one-shots, network_ioctl for everything else. Constants exist for modes 4/8/12, HTTP modes, and translations; pass 6 (directory) and 9 (append) as literals.

network_open(url, OPEN_MODE_HTTP_GET, OPEN_TRANS_NONE);
network_json_parse(url);
network_json_query(url, "/number", buffer);
network_close(url);

→ Writing Cross-Platform Client Apps Using fujinet-lib and fujinet-lib-examples/network/.

A shared-RAM mailbox at $9C00: stage device/command/params/payload, submit by writing SEQ = ACKSEQ + 1 last, poll ACKSEQ, verify the reply. The fujinet.bas library wraps it (fn_transact, fn_param, fn_putstr, net_open/status/read/write/close, api_call). Edges: derive SEQ from the published ACKSEQ; HTTP fires at the first STATUS and the library polls until two STATUS reads agree; declare ASM MEMATTR $8000, $9BFF, "+RWN"; parenthesize (PEEK(x) AND 255). → FujiNet Programming Guide for the Intellivision (intv/fujinet-programmers-guide/).

The network as a DOS — no program required:

NCD N1:TNFS://fujinet.online/     DIR         LOAD GAMES/JUMPMAN.XEX
USER MOLLY                        PASS SECRET
NCD N2:SMB://DEN-PC/ATARI/        NCOPY N1:DOCS/README,N2:BACKUP/README
TYPE N3:HTTPS://fujinet.online/   NTRANS N1: 0

Mounts live in the FujiNet and are shared with whatever you run next; D1:–D8: filespecs forward to N1:–N8: so 1982 programs save to servers unknowingly. Keep mounts off N4: (NOS uses it for NCOPY and HELP). Streams (TCP/SSH/Telnet) are the programmer's guide's department. → NOS: An Introduction (atari/nos_manual/).

Y implemented · S accepted but does nothing (reports success) · – refused/absent · blank = treated as nearest neighbor.

Rough edges as of the colophon's commit, stated plainly:

1. Windows would-block misreport — fujinet-pc Win32 builds report 206 for a would-block socket (fall-through in Protocol.cpp).
2. TCP close-client reports failure on success — ignore $63's transaction status; trust the next status call.
3. Silent stubs — FTP's six filesystem specials; SMB/NFS rename/delete/lock/unlock; base-class lock/unlock inherited by HTTP, S3, GDRIVE, ONEDRIVE. All marked S in the matrix.
4. HTTP stat() short-circuits before its HEAD logic.
5. HTTP header reads lack a length clamp — give them 256-byte buffers.
6. One Telnet state machine (file-scope static) — one TELNET channel at a time.
7. SSH status logic uses an inverted variable name and an unchecked channel pointer; correct for successfully opened channels.
8. is_locked conventions differ — TNFS sets it for writable files, SFTP for read-only ones.
9. Shadowed capability flags in TNFS/FTP/SMB/NFS — harmless (nothing consults them), but a trap for future code.
10. Error 211 (CONNECTION_ABORTED) is defined but never raised.
11. UDP multicast detection exists but is unwired; no group joins.
12. The commit verdict is bus-dependent — the mail/calendar commit-on-close verdict is latched into the next status by the SIO, AdamNet, DriveWire, and RS-232 layers; IEC, IWM, ComLynx, S100, and RC2014 do not yet latch it, so a failed send or commit may not surface there.
13. Draft rejections are one number — every mail or calendar draft error (bad key, missing colon, bad time, missing required field, end before start, mixed date forms) reports 132; the cause is named only in the debug log.
14. No delete, no attachments out — the mail adapters never delete, move, or mark messages and send text/plain only; the calendar adapters compose and edit but cannot remove an event.

The guides differ in spelling; the protocols never do.