Fujitsu PRIMEQUEST Extended Socket inter-partition NIC
A virtual network interface used inside Fujitsu's PRIMEQUEST 2000 E2 and E3 high-end x86 servers, which can be carved into hardware partitions. The Extended Socket device, exposed to Linux as "es0", provides an Ethernet-like link between those partitions without going through an external network. It shipped from the mid-2010s until PRIMEQUEST 2000 sales ended in 2019.
recommendation
Worth keeping but documenting its niche: the hardware is no longer sold (PRIMEQUEST 2000 sales wrapped up by March 2019) yet Fujitsu was still publishing operational manuals for it as recently as 2024, so a real installed base of mission-critical systems still relies on it. The kernel code is also actively maintained, with a 2026 patch reworking its initialization rather than removing it, and there is no generic replacement offering the same partition-to-partition transport.
repository signals
sources
- lore.kernel.org
As of 2026-03-18 the driver still receives upstream changes; the patch 'net: fjes: Drop fjes_acpi_driver and rework initialization' updates initialization rather than proposing driver removal.
- cateee.net
LKDDb identifies CONFIG_FUJITSU_ES as the FUJITSU Extended Socket Network Device driver for Extended Partitioning of FUJITSU PRIMEQUEST 2000 E2 series, with module fjes still present in current kernels.
- fujitsu.com
Fujitsu's PRIMEQUEST 2000 series 2015-model lineup page says sales ended on 2017-06-30; this page includes E2 models such as 2400E2 and 2800E2.
- fujitsu.com
Fujitsu's PRIMEQUEST 2000 series 2016-model lineup page says sales ended on 2019-03-31, supporting that the platform family was no longer widely sold well before 2025.
- fujitsu.com
A Fujitsu manual published in late 2024 still documents loading/unloading the Extended Socket driver and states the device appears as an 'es0' interface on PRIMEQUEST 2400E3/2400E2 and 2800E3/2800E2, indicating lingering deployed systems.
codex reasoning notes (technical)
Kernel-tree inspection via shell showed a real platform net driver under CONFIG_FUJITSU_ES for ACPI-discovered 'Extended Socket'. lore_file_timeline and lore_activity MCP calls showed fresh 2026 maintenance and no removal series, so this is not a dead driver. Web search found LKDDb confirming the hardware scope (PRIMEQUEST 2000 E2 Extended Partitioning) and Fujitsu product pages showing E2/E3 PRIMEQUEST 2000 sales ended by 2019, plus a 2024 Fujitsu manual still documenting operational use. That points to legacy but extant deployments: niche mission-critical installed base, not new sales, and no natural generic replacement for the same partition-to-partition transport.