nsf370 — Network Services Facility for MVS 3.8j

An event-driven networking subsystem for MVS 3.8j whose first responsibility is a native TCP/IP stack — a from-scratch revival of the abandoned mvs38j-ip project (not a port of its Xinu code). The goal is to run existing applications (HTTPD, mvsMF) unchanged, relink-only over a native stack instead of the Hercules X'75' hack, with full EZASOKET / PROFILE.TCPIP compatibility.

Status: M0–M4 complete — foundation, CTCI driver, IPv4/ICMP, sockets + UDP + EZASOKET, and TCP (state machine, data path, retransmission) all run live on Hercules. M5 (Phase 2: the cross-AS NSFS subsystem) is in progress: the app↔stack transport is proven both ways on the live target — an SSI probe (Stage-0a) and, for unauthorized relink-only apps, a private-SVC probe (Stage-0a′, ADR-0038). See CLAUDE.md §7 for the full milestone status.

Documentation

Document	Role
docs/Project-Brief-v2.md	Why / scope / constraints / milestones (frozen)
docs/Architecture-Specification.md	How: interfaces, data structures, lifetimes
CLAUDE.md (repo root)	Operating rules, conventions, milestone status
docs/adr/	Architecture Decision Records

Toolchain

• cc370 — host cross-compile suite (S/370 objects on Linux/macOS)
• libc370 — the cc370 target C library (sysroot; not a project dependency)
• MBT V2 (MVS Build Tools) — build orchestration; mbt is a git submodule

Quick start

git clone --recursive https://github.com/mvslovers/nsf370.git
cd nsf370
cp .env.example .env          # fill in your MVS connection details

make test-host                # build + run the portable tests natively (no MVS)

make run-mvs                  # optional: start a local MVS/CE in Docker
make deps                     # resolve deps + allocate datasets on MVS
make test-mvs                 # deploy + run the tests on MVS

Once there are load modules to build (from M0-2/M1 on), make modules, make package and make deploy build, XMIT and upload them. Run make help for the full target list.

If you cloned without --recursive:

git submodule update --init

Layout

project.toml   MBT V2 project (modules, tests, deps)
Makefile       includes mbt/mk/mbt.mk
src/           portable C sources (nsf*.c)
asm/           HLASM sources (nsf*.asm)
include/       public headers (one per component)
test/          dual host+MVS tests; test/mvs/ MVS-only; test/asm/ asm callers
cfg/           sample PROFILE.TCPIP members
jcl/           install / SAMPLIB jobs
docs/          brief, spec, ADRs   (CLAUDE.md is at the repo root)

License

TBD.