linux-drivers/
drivers/s390/block

IBM Z mainframe DASD, DCSS, and SCM block storage

Block storage drivers for IBM Z mainframes: channel-attached Direct Access Storage Devices (DASD, including the classic ECKD format), Discontiguous Saved Segments (DCSS) shared memory volumes used under z/VM, and Storage Class Memory (SCM) flash. These are the primary disk paths for Linux running in an LPAR, as a z/VM guest, or as a KVM guest on IBM Z hardware, from the 1990s through today.

keep conf=0.88 deploy=medium replacement=none subsystem=s390 category=storage-block
88%

recommendation

It should stay in the kernel because IBM Z mainframes are very much still being sold new — IBM announced the z17 in April 2025 — and DASD remains the standard way Linux on Z talks to mainframe storage. The code is also actively maintained upstream, with patches from IBM landing on the linux-block and linux-s390 lists as recently as late 2025, and IBM continues to document these drivers as required components for current Linux on IBM Z deployments.

repository signals

22 files
25,336 source lines
178 commits, 5y
+2,745 / −2,406 lines added / removed, 5y
43 authors, 5y
monthly commits · 2021-04-21 → 2026-04-21 · 178 total · active in 51/61 months
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sources

  1. lore.kernel.org

    `drivers/s390/block/dasd.c` still receives recent upstream maintenance in late 2025, with review on linux-block/linux-s390.

  2. ibm.com

    IBM still documents the DASD driver for current Linux on IBM Z environments, including LPAR, z/VM guest, and KVM guest, and describes DASD as access to real or emulated IBM mainframe storage.

  3. ibm.com

    Current IBM docs still instruct users how to prepare ECKD DASDs and state the DASD driver components must be built in or loaded, indicating ongoing supported deployment.

  4. newsroom.ibm.com

    IBM announced the z17 mainframe on April 8, 2025, showing IBM Z hardware is still sold new in 2025.

codex reasoning notes (technical)

Not an early-exit case: local shell inspection showed real block-driver sources (`dasd*`, `dcssblk`, `scm_blk`) plus driver entry points and Kconfig options. `lore_activity` on `drivers/s390/block/dasd.c` returned recent 2025 patches via lore URL, so there is active upstream maintenance rather than removal. IBM docs URLs were obtained by web search and show current DASD/ECKD usage on Linux on IBM Z; IBM z17 newsroom URL was obtained by web search and supports `hardware_still_sold_new_in_2025=true`. No natural upstream replacement covers the same channel-attached DASD/DCSS/SCM use case; `zfcp` is a different storage path, not a replacement.