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The FujiNet Network Protocol Handbook

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

Part I — The Network Device Model

Introduction

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:

Open — devicespec + access mode (aux1) + translation mode (aux2).
Status — bytes waiting, connection state, error code.
Read / write — move bytes.
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.

The scheme table

Scheme	Class	Reaches
`TNFS`	NetworkProtocolTNFS	TNFS file servers
`SD`	NetworkProtocolSD	the FujiNet's own SD card
`SMB`	NetworkProtocolSMB	Windows / Samba shares
`NFS`	NetworkProtocolNFS	UNIX NFSv3 exports
`FTP`	NetworkProtocolFTP	FTP servers (anonymous)
`SFTP`	NetworkProtocolSFTP	files over SSH
`HTTP` `HTTPS`	NetworkProtocolHTTP	web servers, REST APIs, WebDAV
`S3`	NetworkProtocolS3	Amazon S3 and compatibles
`GDRIVE`	NetworkProtocolGDRIVE	Google Drive
`ONEDRIVE`	NetworkProtocolONEDRIVE	Microsoft OneDrive
`TCP`	NetworkProtocolTCP	raw sockets, client or server
`UDP`	NetworkProtocolUDP	datagrams
`TELNET`	NetworkProtocolTELNET	negotiated Telnet
`SSH`	NetworkProtocolSSH	an interactive SSH shell
`WS` `WSS`	NetworkProtocolWS/WSS	WebSockets, plain or TLS
`SSH.KEYGEN`	NetworkProtocolSSHKeygen	generate the SSH key pair
`SSH.COPYID`	NetworkProtocolSSHCopyId	install it on a server
`CLIPBOARD`	NetworkProtocolClipboard	the FujiNet clipboard + history
`CPM`	NetworkProtocolCPM	a CP/M 2.2 machine inside the FujiNet
`GMAIL`	NetworkProtocolGMAIL	a Gmail mailbox — read, compose, reply
`IMAPS`	NetworkProtocolIMAPS	any IMAP mailbox over TLS
`GCAL`	NetworkProtocolGCAL	Google Calendar — read, compose, edit
`ICAL` `WEBCAL` `ICALH`	NetworkProtocolICAL	published iCalendar feeds
`TEST`	NetworkProtocolTest	a fixed test pattern / adapter skeleton

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

The Devicespec

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.

Open Modes and Translation

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.

aux2	Network EOL
0	none — binary, untouched
1	CR (`$0D`)
2	LF (`$0A`)
3	CR/LF
4	PETSCII character translation (on top of the stream)

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.

Channel Modes: Protocol, JSON, and SGML

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

Open the URL, set channel mode JSON ($FC aux2=1).
Parse ($50 'P') — the FujiNet builds the document tree.
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, Errors, and Interrupts

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).

The error table

Code	Meaning	Code	Meaning
1	success	202	socket timeout
131	write only	203	network down
132	invalid command	204	connection reset
135	read only	205	connect in progress
136	end of file	206	address in use
138	timeout	207	not connected
144	general fatal	208	server not running
146	not implemented	209	no connection waiting
151	file exists	210	service unavailable
162	no space	211	connection aborted (never raised)
165	invalid devicespec	212	bad username/password
166	invalid point	213	could not parse JSON
167	access denied	214	HTTP 4xx client error
170	file not found	215	HTTP 5xx server error
200	connection refused	255	out of buffers
201	network unreachable

Special Commands

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

Hex	Dec	Char	Command
`$20`	32		rename (`old,new` in one devicespec)
`$21`	33	`!`	delete
`$23`/`$24`	35/36	`#` `$`	lock / unlock
`$25`/`$26`	37/38	`%` `&`	seek (POINT) / tell (NOTE)
`$2A`/`$2B`	42/43	`*` `+`	mkdir / rmdir
`$2C`/`$30`	44/48	`,` `0`	chdir / getcwd
`$41`/`$63`	65/99	`A` `c`	TCP accept / close client
`$44`/`$72`	68/114	`D` `r`	UDP set destination / get remote
`$4C`	76	`L`	set native EOL
`$4D`	77	`M`	HTTP channel mode
`$50`/`$51`	80/81	`P` `Q`	JSON/SGML parse / query
`$54`	84	`T`	sticky translation
`$5A`	90	`Z`	interrupt rate
`$FB`	251		JSON parameters
`$FC`	252		channel mode (protocol/JSON/SGML)
`$FD`/`$FE`	253/254		username / password
`$FF`	255		data-direction inquiry (how NDEV relays unknowns)

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.

Part II — Filesystem Protocols

The Filesystem Model

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:

aux2	Format
< 128	classic 8.3 short entries (sizes in `FSSectorSize` sectors)
128	long filename, platform width (37 / ADAM 30 / CoCo 31)
129	Apple II 80-column
130	long + provider file ID (GDRIVE)
131	RAW — filename only, `/` marks directories; for programs
132	ProDOS 40-col CAT (real dates only from TNFS)
133	ProDOS 80-col CATALOG

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.

TNFS

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.

SD

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.

SMB

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.

NFS

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.

FTP

N:FTP://host[:port]/path — always anonymous (anonymous/fujinet@fujinet.online); 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.

SFTP

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.

HTTP and HTTPS

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

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

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

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.

Part III — Stream Protocols

TCP

Devicespec	Meaning
`N:TCP://host:port/`	connect
`N:TCP://host/`	connect, port 23
`N:TCP://:port/`	listen
`N:TCP://`	empty channel

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.

UDP

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.

TELNET

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.

SSH

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.

WS and WSS

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.

Part IV — Session Utilities

SSH.KEYGEN

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.

SSH.COPYID

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.

CLIPBOARD

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.

CPM

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.

TEST

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.

Part V — Mail and Calendar

The Mailbox Model

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

Path	aux1	Returns
`/FOLDER`	4	message count
`/FOLDER`	6	message index
`/FOLDER/N`	4	message N's body
`/FOLDER/N`	6	attachment index
`/FOLDER/N/A`	4	attachment data (0 = body)
`/`	8	compose a new message (write, then close)
`/FOLDER/N`	8	reply to message N

?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: alice@example.com
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

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

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).

The Calendar Model

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

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, WEBCAL, and ICALH

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.

Part VI — From Your Machine

Atari BASIC

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/).

Applesoft BASIC

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.

Coleco ADAM SmartBASIC 1.x

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.

C with fujinet-lib

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/.

IntyBASIC on the Intellivision

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/).

FujiNet NOS

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/).

Appendix — Protocol Capability Matrix

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

Protocol	R	W	A	RW	DIR	SEEK	REN	DEL	MKD	RMD	LCK	UNL	Port / notes
TNFS	Y	Y	Y	Y	Y	Y	Y	Y	Y	Y	Y	Y	16384 · anonymous
SD	Y	Y	Y	Y	Y	Y	Y	Y	Y	Y	–	–	local card
SMB	Y	Y	Y	Y	Y	Y	S	S	Y	Y	S	S	445 · URL or specials
NFS	Y	Y	Y	Y	Y	Y	S	S	Y	Y	S	S	2049 · UID/GID
FTP	Y	Y	–	–	Y	–	S	S	S	S	S	S	21 · anonymous only
SFTP	Y	Y	Y	Y	Y	Y	Y	Y	Y	Y	Y	Y	22 · pass or key
HTTP/S	Y	Y	–	Y	Y	Y	Y	Y	Y	Y	S	S	80/443 · WebDAV ops
S3	Y	Y	Y	Y	Y	–	Y	Y	Y	Y	S	S	443 · keys or config
GDRIVE	Y	Y	Y	Y	Y	–	S	Y	Y	Y	S	S	OAuth (web UI)
ONEDRIVE	Y	Y	Y	Y	Y	–	Y	Y	Y	Y	S	S	OAuth (web UI)
TCP	Y	Y		Y	–	–	–	–	–	–	–	–	23 dflt · listen + accept
UDP	Y	Y		Y	–	–	–	–	–	–	–	–	port required
TELNET	Y	Y		Y	–	–	–	–	–	–	–	–	23 · negotiated
SSH	Y	Y		Y	–	–	–	–	–	–	–	–	22 · pass or key
WS/WSS	Y	Y		Y	–	–	–	–	–	–	–	–	80/443 · frames
SSH.KEYGEN	Y	–			–	–	–	–	–	–	–	–	report only
SSH.COPYID	Y	–			–	–	–	–	–	–	–	–	pass required
CLIPBOARD	Y	Y	Y	Y	–	–	–	–	–	–	–	–	index 0 writable
CPM	Y	Y		Y	–	–	–	–	–	–	–	–	console channel
GMAIL	Y	Y	–	–	Y	–	–	–	–	–	–	–	OAuth · W = compose/reply
IMAPS	Y	–	–	–	Y	–	–	–	–	–	–	–	993 · read-only
GCAL	Y	Y	–	Y	Y	–	–	–	–	–	–	–	OAuth · W = compose/edit
ICAL	Y	–	–	Y	Y	–	–	–	–	–	–	–	feeds · read-only
TEST	Y	Y	Y	Y	–	–	–	–	–	–	–	–	loopback

Appendix — Scheme Quick Reference

Scheme	Canonical form · query parameters
`TNFS`	`N:TNFS://host[:port]/path`
`SD`	`N:SD:/path`
`SMB`	`N:SMB://[user:pass@]server/share/path`
`NFS`	`N:NFS://host[:port]/export/path`
`FTP`	`N:FTP://host[:port]/path`
`SFTP`	`N:SFTP://user[:pass]@host[:port]/path`
`HTTP` `HTTPS`	`N:HTTPS://[user:pass@]host[:port]/path[?query]`
`S3`	`S3://[key:secret@]endpoint[:port]/bucket/key` · `?region=` `?tls=0\|1`
`GDRIVE`	`GDRIVE:///path`
`ONEDRIVE`	`ONEDRIVE:///path`
`TCP`	`N:TCP://host[:port]/` · `N:TCP://:port/` (listen)
`UDP`	`N:UDP://[host]:port/`
`TELNET`	`N:TELNET://host[:port]/` · `?term=` `?cols=` `?rows=`
`SSH`	`N:SSH://user[:pass]@host[:port]/` · `?term=` `?cols=` `?rows=`
`WS` `WSS`	`N:WSS://host[:port]/path` · `?frame=text`
`SSH.KEYGEN`	`N:SSH.KEYGEN://ed25519/` · `?overwrite=1`
`SSH.COPYID`	`N:SSH.COPYID://user:pass@host[:port]/`
`CLIPBOARD`	`N:CLIPBOARD:///[0-9]` · `?binary=1`
`CPM`	`N:CPM://`
`TEST`	`N:TEST://anything/`
`GMAIL`	`GMAIL:///Folder[/N[/A]]` · `?range=a-b` `?newest=0\|1` · mode 8: `/` compose, `/Folder/N` reply
`IMAPS`	`IMAPS://user:pass@host[:port]/FOLDER[/N[/A]]` · `?range=` `?newest=` (read-only)
`GCAL`	`GCAL:///[sel]/VIEW[/DATE[/N]]` · `?category=` `?count=` `?days=` `?wkst=` `?tz=` · mode 8: `/[sel]` compose, `/…/N` edit
`ICAL` `WEBCAL` `ICALH`	`ICAL://feed-host/feed-path/VIEW[/DATE[/N]]` · same as GCAL

Appendix — Implementation Notes

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

Windows would-block misreport — fujinet-pc Win32 builds report 206 for a would-block socket (fall-through in Protocol.cpp).
TCP close-client reports failure on success — ignore $63's transaction status; trust the next status call.
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.
HTTP stat() short-circuits before its HEAD logic.
HTTP header reads lack a length clamp — give them 256-byte buffers.
One Telnet state machine (file-scope static) — one TELNET channel at a time.
SSH status logic uses an inverted variable name and an unchecked channel pointer; correct for successfully opened channels.
is_locked conventions differ — TNFS sets it for writable files, SFTP for read-only ones.
Shadowed capability flags in TNFS/FTP/SMB/NFS — harmless (nothing consults them), but a trap for future code.
Error 211 (CONNECTION_ABORTED) is defined but never raised.
UDP multicast detection exists but is unwired; no group joins.
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.
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.
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.

Appendix — The Programmer's Guides

Guide	Where
FujiNet Programming Guide for the Atari	`fujinet-manuals/atari/programmers_guide/`
FujiNet BASIC Extension for the Apple II	`fujinet-manuals/apple2/basic_extension/`
FujiNet Programming Guide for the Apple II	`fujinet-manuals/apple2/programmers_guide/`
FujiNet Programming Guide for the Coleco ADAM	`fujinet-manuals/adam/programmers_guide/`
SmartBASIC 1.x FujiNet appendix	the `smartbasic-1.x` repository
FujiNet Programming Guide for the Intellivision	`fujinet-manuals/intv/fujinet-programmers-guide/`
Writing Cross-Platform Client Apps Using fujinet-lib	`fujinet-manuals/writing-cross-platform-client-apps-using-fujinet-lib/`
NOS: An Introduction	`fujinet-manuals/atari/nos_manual/`
FujiNet Programmer's Reference (MS-DOS)	`fujinet-manuals/msdos/programmers_reference/`

The guides differ in spelling; the protocols never do.

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