PuTTY

---=== PuTTY on AmigaOS4 ===---

--The Port

The AmigaOS4 port provides the PuTTY 0.85 suite with a native ReAction interface. Its configuration pages, menus and controls follow the original Windows version as closely as native OS4 gadgets allow. The SSH protocols, terminal emulator, key formats and command-line tools retain the upstream PuTTY implementation.

All eight programs are included: putty, puttytel, pterm, pageant, puttygen plink, pscp and psftp:

• PuTTY provides the full connection frontend.
• PuTTYtel provides the non-SSH variant.
• Pterm is a local terminal with PuTTY's configuration options.
• Pageant manages authentication keys.
• PuTTYgen creates and converts keys.
• Plink, PSCP and PSFTP provide command-line tools.

--Runtime

The programs use newlib without an OpenSSL or AmiSSL dependency. PuTTY provides its own SSH implementation, cryptographic algorithms and cryptographic random-number generator. Secure seed material comes directly from 'timer.device''s 'UNIT_ENTROPY' through 'TR_READENTROPY': the same native entropy source used by AmiSSL on AmigaOS4. While Fredrik's (Salass00) SSHTerm uses libssh2 for SSH and AmiSSL for cryptography, PuTTY provides both implementations itself.

The binaries are built with '-O3' and a 1 MiB stack cookie. They do not use SJLJ exception handling or link GCC's generic emutls runtime. Instead of '-athread=native' from adtools, a private pthread/gthread-compatible runtime uses native Exec/DOS workers, signals, mutexes, conditions and task-specific storage.

The minimum version is dos.library 54.120, which fixes a lost-wakeup race in 'WaitForChildExit'. The native worker runtime relies on this fix.

--ReAction Interface

All windows use 'window.class' and its 'WM_OPEN'/'WM_HANDLEINPUT' lifecycle.

Layout, buttons, strings, checkboxes, radio buttons, choosers, list browsers and scrollers are native ReAction objects. Colour modification uses 'getcolor.gadget' with its native colour requester.

File and font selection use ASL requesters, messages and About windows use 'requester.class', and menu strips and submenus use native menu objects.

The Host Name field receives focus when configuration opens. Together with the underlined keyboard shortcuts on pushbuttons, this lets you enter a host name and connect without using the mouse.

Change Settings remains usable alongside the live terminal and does not block terminal input.

--Terminal Engine and Rendering

The terminal is PuTTY's own emulator, with its escape-sequence parser, character translation, Unicode handling, selection and compressed scrollback. Remote sessions are not rendered by 'console.device' or 'texteditor.gadget': the frontend draws PuTTY's terminal cells through 'graphics.library' and 'diskfont.library'.

The terminal is optimised for fast rendering, scrolling and screen updates.

Ordinary fixed-width text is batched into neighbouring runs. 'graphics.library' 'Text()' draws each run into a reusable small RAM strip using 'JAM2', which writes the foreground and background together. 'BltBitMapTags' transfers the occupied run into the native backing bitmap. Blank areas use 'RectFillColor'. Unicode outline glyphs use diskfont glyph maps and 'BltTemplate'. The changed screen region is presented with 'BltBitMapRastPort', clipped to the window interior.

Small scrolls move existing pixels and reuse terminal row data, then draw exposed or changed rows. Unchanged rows avoid text-run assembly. Pending scrollbar positions are coalesced, redundant scroller notifications are ignored, and manual scrolling does not wait for the terminal's incoming-output repaint delay. This path avoids a full-window RAM upload or video-memory readback. It still has the small text-strip and backing-bitmap blits described above. Graphics locks cover only the operation that needs them and are released immediately.

The terminal uses the system's default font and size unless overridden in the session settings, and works best with a fixed-width font. Its native window has a thin bottom border and a right-border scroller, with single-line mouse-wheel scrolling and a configurable scrollback buffer.

--Window Menu and Fullscreen

Use RMB over the terminal title, border or screen menu bar to open the native terminal menu. It follows PuTTY's original grouping, including Special Commands and Saved Sessions submenus, Event Log, Duplicate Session, Change Settings, Copy All to Clipboard, Clear Scrollback and Reset Terminal. RMB inside the terminal text area retains its configured paste behaviour. Clipboard exchange uses 'clipboard.device' to exchange text with other Amiga applications.

Amiga-F toggles fullscreen. The frontend opens a private screen with SA_LikeWorkbench and a borderless window covering it, without a scrollbar. The same connection and terminal contents remain active. Returning restores the normal window and scroller. Alt-Enter also toggles fullscreen when Full screen on Alt-Enter is enabled under Window / Behaviour.

--Pterm and the AmigaDOS Shell

Pterm combines the same PuTTY terminal engine and native renderer with a real AmigaDOS Shell. The Shell executes 'S:Shell-Startup', so its aliases, prompt and local settings are applied normally. Pterm interprets the resulting terminal output; it does not reimplement the Shell script language. An explicit command supplied with '-e' follows its separate noninteractive startup path.

A native DOS-packet console provides input, output, waiting and cooked/raw mode handling. Cooked input includes editing, history and file/command completion. Amiga-specific display controls are handled alongside PuTTY's ANSI terminal parsing, including the single-byte CSI form, display-background selection and saved colour defaults.

Local console colours are obtained through 'ObtainConsoleData' and the console preference API, with 'ENV:Sys/console.prefs' as a fallback. System pens, full ANSI colours, faint ANSI colours and user colours are respected. Local Amiga colours remain separate from the PuTTY palette used by a remote session. Plink running inside pterm switches to the remote terminal context and restores the local context on return.

Pterm retains PuTTY's selection, clipboard, cursor, font and scrollback controls. While another command owns the console, close requests are ignored and the command remains usable. After the command exits, click Close again to close the window.

--Plink, PSCP and PSFTP

Plink is useful for quick command-line connections, remote commands, scripts and batch jobs without opening PuTTY's GUI. Its upstream options also support tunnels, local/remote forwarding, dynamic SOCKS proxies and connections through configured proxies. Use '-t' when an interactive remote terminal is required; '-s' selects an SSH subsystem, not a normal login shell.

When run from a native Amiga console, Plink uses its Amiga terminal context; inside pterm it can use the PuTTY/xterm context. A configured terminal type or 'TERM' setting can override the default.

PSCP provides command-line file copying using SFTP by default or the legacy SCP protocol with '-scp'.

PSFTP provides an interactive SFTP prompt and batch files with '-b'. SFTP is an SSH file-transfer protocol, not FTP.

--PuTTYgen

PuTTYgen has a full native ReAction GUI following the Windows application: its initial view, mouse-entropy collection view and generated/loaded-key view show the corresponding controls at the appropriate stage. File, Key, Conversions and Help menus retain the original operations and terminology.

Move the mouse over the blank collection area after clicking Generate. The collection progress advances with mouse input and pauses when that input stops. The following progress phase is the actual key computation in a native worker. Secure OS entropy is also used. The key algorithms, PPK formats, encryption and conversions come from upstream PuTTY. Encrypted RSA, Ed25519 and ECDSA key files have been checked with upstream tools. This is the Windows-style GUI program with its applicable command-line interface, rather than the Unix batch-only frontend.

--Pageant and Connection Sharing

Pageant is a separate native key-agent program, as in the original suite. Add PuTTY private key files through Add Key or run 'pageant key.ppk'. Unlock encrypted keys once; PuTTY and the command-line tools can then request authentication through the agent. The server must authorize the matching public key, and Attempt authentication using Pageant must be enabled. Remove Key, Remove All and quitting the agent discard loaded keys. Native Exec message ports provide local communication without a TCP listener.

SSH connection sharing uses native local IPC too. Enable Share SSH connections if possible under Connection / SSH before connecting, or use '-share'. Duplicate Session can reuse the authenticated connection for another shell without another login. Pageant is not required for sharing. Closing the upstream window disconnects its shared sessions; exiting only its remote shell keeps those sessions running until the last one ends.

--Settings, Paths and Help

Saved settings, host keys and random-seed data are kept in 'PROGDIR:config', or in the drawer selected by 'PUTTYDIR'. Serial connections use device/unit names such as 'serial.device/0'. Native terminal printing writes through 'PRT:'.

Local proxy commands are executed through the AmigaDOS Shell.

Help opens this file, 'PROGDIR:docs/PuTTY.guide'. The manual chapters retain the upstream text, converted from 'putty.chm' to AmigaGuide, with this AmigaOS4 chapter added.

--Network Support and Remaining Platform Limits

Networking uses 'bsdsocket.library'. This build supports IPv4 only;IPv6 and GSSAPI support, including Kerberos single sign-on through GSSAPI, are disabled. Password and public-key SSH authentication, connection sharing, proxies, TCP port forwarding and SFTP/SCP remain available.

Windows process-ACL restrictions and Unix-specific facilities such as X resources and utmp login accounting do not apply to this port. X11 forwarding remains available to an X server reachable over TCP/IP.

Pterm does not implement every direct 'console.device' operation. Programs requiring such operations may not work correctly.

The serial backend supports one or two stop bits, with no flow control, XON/XOFF or RTS/CTS, subject to driver and hardware support. The standard 'serial.device' interface does not expose settings for 1.5 stop bits or DSR/DTR flow control, so these modes are not implemented.

--Bugs

The suite has been tested with bidirectional serial connections, SSH connections to different servers, Telnet connections to routers and proxy configurations. Bugs are still possible. Please report them at: https://github.com/kas1e/putty/

--Credits

PuTTY is by Simon Tatham and the PuTTY contributors.

AmigaOS4 port is by Roman "kas1e" Kargin.

09/11/2026