Iron 3270

A real IBM 3270 terminal for z/OS and z/VM, right inside Visual Studio Code.

Block-mode 3270 screens, the full PF/PA keyboard, verified TLS, IND$FILE file transfer and macros, in an editor tab next to your code. Big iron, in your editor.

Website · Quick guide · Screenshots · Support

Preview release. Tested against real systems: z/OS with TSO/ISPF and CICS, z/VM, and MVS 3.8j. Feedback is very welcome at spiersall@gmail.com.

Features

• A real 3270, not a scrolling shell. Protected and numeric fields, modified data tags, keyboard locking and type-ahead, on models 2–5 (up to 27×132) as 3278 or 3279, over TN3270 or TN3270E, with an authentic operator information area.
• Every key you need. PF1–PF24, PA1–PA3, Enter, Clear, Reset, Attn, SysReq, Erase EOF, Erase Input, Dup and Field Mark, on your keyboard or on a dockable on-screen 3270 keyboard. Keymaps are fully customizable.
• Connections in the Activity Bar. Save hosts, group them, and double-click to connect. Each session opens in its own editor tab, so splits and side-by-side work just work.
• TLS done carefully. Certificates and host names are verified by default. Trust your company's CA, or pin one certificate after reviewing it. There is no "accept anything" switch.
• IND$FILE transfers. Send and receive files with TSO, CMS and CICS: text or binary, RECFM, LRECL, BLKSIZE and space allocation, batches of PDS members, progress and cancel.
• Editing that respects fields. Block selection, field-aware paste, Select JCL and Paste JCL, nine clipboard buffers, screen history, find, and clickable URLs.
• Macros. Record or write simple .3270macro scripts that wait for the real screen state. Passwords are never recorded.
• Private by design. No telemetry. Passwords live in VS Code's secure storage and never appear in logs, macros or exported connections.

Getting started

1. Click the Iron 3270 icon in the Activity Bar, then Add Connection.
2. Enter the host, the port (23, or 992 for TLS), the terminal model and the host code page. Choose TLS: verify certificate whenever your host supports it, and use Test Connection to check.
3. Double-click the connection to open a session. Use Send and Receive on the toolbar to transfer files.

Default keys

While a terminal tab has focus, F1 sends PF1 instead of opening the Command Palette. PCOMM- and x3270-style keymaps are built in, and the keymap editor lets you change any key.

Platforms

Security and privacy

• TLS certificates and host names are verified by default. The alternatives are a CA you trust or one pinned certificate, and a session-only exception always shows a warning.
• Client-certificate passphrases are kept in VS Code's SecretStorage.
• Macros cannot read files, start programs or reach the network.
• Iron 3270 sends no telemetry. Screen contents and keystrokes are never logged.

Support

Questions, problems or ideas: email spiersall@gmail.com, or see the support section of the website for what to include in a report.

License and credits

Iron 3270 is free and licensed under BSD-3-Clause.

The protocol engine is b3270 from the x3270 suite by Paul Mattes and contributors. The 3270 font is by Ricardo Banffy. Third-party licenses are listed in THIRD-PARTY-NOTICES.md, which is included with the extension.

IBM, z/OS, z/VM, CICS and ISPF are trademarks of IBM. Iron 3270 is an independent project and is not affiliated with IBM, the x3270 project, or Tom Brennan Software (Vista TN3270).