--- name: "isa" section: "4" platform: "openbsd" package: "man" version: "8.0-current-20261101" release: "OpenBSD 8.0-current (2026-11-01)" platforms: ["openbsd"] url: "https://new.carta.tech/isa" --- # isa(4) introduction to ISA bus support ## NAME **isa**, **isadma** – introduction to ISA bus support ## SYNOPSIS **# amd64 and i386** **isa\* at amdpcib?** **isa0 at tcpcib?** **isa0 at mainbus0** **isa0 at pcib?** **isadma0 at isa?** **# i386** **isa0 at ichpcib?** **isa\* at glxpcib?** **isa0 at gscpcib?** **# alpha** **isa\* at pceb?** **isa\* at sio?** **isadma0 at isa?** **# loongson** **isa\* at glxpcib?** ## DESCRIPTION The system includes a machine-independent ISA bus subsystem and several machine-independent ISA device drivers. Attachments are machine-dependent and depend on the bus topology and ISA bus interface of the system. Drivers able to use DMA attach at **isadma**; otherwise they attach at **isa**. Note that interrupt mappings on the i386 may require that the BIOS be configured to reserve the interrupts for these devices as "Legacy ISA". If such configuration is not done, the system may use those interrupts for [pci(4)](/pci/4.md) or [isapnp(4)](/isapnp/4.md) devices instead. OpenBSD provides support for the following devices. Note that not all architectures support all devices. ### SCSI controllers - [ahc(4)](/ahc/4.md) Adaptec VL/EISA/PCI SCSI interface - [aic(4)](/aic/4.md) Adaptec AIC-6260 and AIC-6360 SCSI interface - [uha(4)](/uha/4.md) Ultrastor SCSI interface - [wds(4)](/wds/4.md) WD7000 compatible ISA SCSI interface ### Disk and tape controllers - [fdc(4)](/fdc/4.md) NEC765 compatible floppy disk driver - [wdc(4)](/wdc/4.md) Standard Western Digital type hard drive controllers: MFM, RLL, ESDI, and IDE/ATAPI. See also the [pciide(4)](/pciide/4.md) device driver which is used instead on machines with PCI IDE controllers. ### Serial and parallel interfaces - [addcom(4)](/addcom/4.md) Addonics FlexPort 8S serial communication cards - [ast(4)](/ast/4.md) multiplexing serial communications interface - [boca(4)](/boca/4.md) multiplexing serial communications interface - [com(4)](/com/4.md) serial communications interface - [cy(4)](/cy/4.md) Cyclades Cyclom-{4, 8, 16}Y asynchronous comms board device driver - [hsq(4)](/hsq/4.md) multiplexing serial communications interface - [lpt(4)](/lpt/4.md) parallel port driver ### Network interfaces - [ec(4)](/ec/4.md) 3Com EtherLink II (3c503) Ethernet device - [ef(4)](/ef/4.md) 3Com Fast EtherLink ISA (3c515) 10/100 Ethernet device - [eg(4)](/eg/4.md) 3Com EtherLink Plus Ethernet (3c505) Ethernet device - [el(4)](/el/4.md) 3Com EtherLink (3C501) Ethernet device - [ep(4)](/ep/4.md) 3Com EtherLink III and Fast EtherLink III 10/100 Ethernet device - [ex(4)](/ex/4.md) Intel EtherExpress Pro/10 and Pro/10+ Ethernet device - [ie(4)](/ie/4.md) Intel i82586/i82596 Ethernet device - [lc(4)](/lc/4.md) DEC EtherWORKS III 10/100 Ethernet device - [le(4)](/le/4.md) AMD LANCE Ethernet device - [ne(4)](/ne/4.md) NE2000 and compatible 10/100 Ethernet device - [sm(4)](/sm/4.md) SMC91C9x and SMC91C1xx-based 10/100 Ethernet device - [we(4)](/we/4.md) Western Digital/SMC WD80x3, SMC Elite Ultra, and SMC EtherEZ Ethernet device ### Sound cards - [ess(4)](/ess/4.md) ESS Technology AudioDrive family audio device - [gus(4)](/gus/4.md) Gravis UltraSound/UltraSound MAX audio device - [mpu(4)](/mpu/4.md) Roland/Yamaha MPU401 MIDI UART device - [pas(4)](/pas/4.md) Media Vision Pro AudioSpectrum audio device - [sb(4)](/sb/4.md) SoundBlaster family audio device ### Hardware Sensors - [aps(4)](/aps/4.md) ThinkPad Active Protection System accelerometer - [asmc(4)](/asmc/4.md) Apple System Management Controller (SMC) - [fins(4)](/fins/4.md) Fintek F71805F LPC Super I/O - [it(4)](/it/4.md) ITE IT87xxF and SiS SiS950 temperature, voltage, and fan sensor with watchdog timer - [lm(4)](/lm/4.md) National Semiconductor LM78/79/81 temperature, voltage, and fan sensor - [nsclpcsio(4)](/nsclpcsio/4.md) National Semiconductor PC87366 LPC Super I/O with GPIO - [schsio(4)](/schsio/4.md) SMSC SCH311x LPC Super I/O - [uguru(4)](/uguru/4.md) ABIT temperature, voltage and fan sensors - [viasio(4)](/viasio/4.md) VIA VT1211 LPC Super I/O - [wbsio(4)](/wbsio/4.md) Winbond LPC Super I/O ### Miscellaneous devices - [gscsio(4)](/gscsio/4.md) National Semiconductor Geode SC1100 I2C controller - [isagpio(4)](/isagpio/4.md) ISA I/O mapped as GPIO - [joy(4)](/joy/4.md) games adapter - [lms(4)](/lms/4.md) Logitech-style bus mouse driver - [mms(4)](/mms/4.md) Microsoft-style bus mouse driver - [npx(4)](/npx/4.md) Numeric Processing Extension coprocessor and emulator - [pcdisplay(4)](/pcdisplay/4.md) PC display adapter driver for wscons - [pcic(4)](/pcic/4.md) ISA PCMCIA controllers - [pckbc(4)](/pckbc/4.md) PC (ISA) keyboard controller driver - [pcppi(4)](/pcppi/4.md) PC (ISA) control and timer port driver - [skgpio(4)](/skgpio/4.md) Soekris net6501 GPIO and LEDs driver - [tcic(4)](/tcic/4.md) Databook PCMCIA controller driver - [vga(4)](/vga/4.md) VGA graphics driver for wscons - ykbec(4) Ene Technology KB3310B embedded controller chip Note that some ISA devices also have newer ISA Plug-and-Play variants. These are listed in [isapnp(4)](/isapnp/4.md). ## SEE ALSO [intro(4)](/intro/4.md), [isapnp(4)](/isapnp/4.md) ## HISTORY The machine-independent ISA subsystem appeared in OpenBSD 2.0.