Release notes for Model 204 version 8.0

Overview

These release notes contain installation and features information for the Rocket Model 204 version 8.0 release. Before beginning your installation, please read through this information about product installation and changes.

Janus product enhancements

TLS 1.3 support

Janus SSL ports now support TLS 1.3 (RFC 8446) for both client and server connections. TLS 1.3 provides improved security and performance over TLS 1.2, including a simplified handshake with fewer round trips, and the removal of legacy features such as renegotiation.

The following TLS 1.3 cipher suites are supported:

• TLS_AES_128_GCM_SHA256
• TLS_AES_256_GCM_SHA384

Key exchange is performed using X25519 (Curve25519 Elliptic Curve Diffie-Hellman, per RFC 7748). Certificate authentication uses RSA-PSS signatures.

Key derivation uses the HKDF-based key schedule defined in RFC 8446, replacing the PRF-based approach of earlier TLS versions.

TLS 1.3 is enabled by default on ports that allow TLS 1.2. To restrict a port to earlier protocol versions, use the existing SSLVERSION parameter on the JANUS DEFINE command.

Client-side TLS 1.3 and post-handshake authentication

Janus client connections (for example, $SOCK-based clients and Janus Web Server outbound HTTPS requests) now negotiate and complete a full TLS 1.3 handshake as the client, including X25519 key exchange, the HKDF-based key schedule, and RSA-PSS certificate verification of the server.

Client certificate authentication is supported both during the initial handshake and after it completes. When a TLS 1.3 server sends a post-handshake CertificateRequest (RFC 8446 Section 4.6.2) — for example, when a server application requests a client certificate on a connection that did not originally require one — the Janus client automatically responds with its Certificate, CertificateVerify, and Finished messages, allowing the authenticated request to proceed without interrupting the connection.

No application changes are required. Post-handshake authentication is used automatically when a server requests it and a client certificate is available for the port.

Imagine Transparency support

A new facility called Imagine Transparency is now available to allow files in an Imagine database to be accessed from Model 204 as if they were native files.

A new port type, IMAGINET, is now available. It allows Model 204 files to be stored on an Imagine server rather than in operating system files. A new parameter is now available on the ALLOCATE command to indicate that a file is to be accessed via the IMAGINET port rather than from operating system files.

Performance enhancements

Hardware-accelerated deflate/inflate compression

The SOUL compression functions (Deflate, Inflate, Gzip, Gunzip, Zip, and Unzip) now exploit the IBM z15 (and above) DFLTCC (Deflate Conversion Call) hardware instruction when available. This provides significant performance improvement for compression and decompression of longstrings without any application code changes.

Hardware acceleration is used automatically when the processor supports it. On processors without DFLTCC support, the existing software implementation continues to be used transparently.

The DFLTCC instruction handles both the deflate (compress) and inflate (expand) operations natively in hardware, including CRC-32 computation, providing throughput improvements that scale with data size.

New and changed commands

DISPLAY DSNAMES command