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Special Forums Hardware Filesystems, Disks and Memory What is the difference between o_direct and DAX with ext4 filesystem? Post 302982267 by Corona688 on Tuesday 27th of September 2016 11:10:28 AM
Old 09-27-2016
Usually, direct I/O is a bad idea. What are you attempting to accomplish? pmem uses DAX already.

DAX is intended for RAM or RAM-like devices with page sizes identical to the system page size. It avoids an extra copy-between-kernel step that may otherwise happen the first time a page is read using block devices, even RAM ones.

In other words, DAX is direct I/O specially optimized for RAM.

Last edited by Corona688; 09-27-2016 at 12:15 PM..
 

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socal(7D)							      Devices								 socal(7D)

NAME
socal - Serial Optical Controller for Fibre Channel Arbitrated Loop (SOC+) device driver SYNOPSIS
socal@sbus-slot,0 DESCRIPTION
The Fibre Channel Host Bus Adapter is an SBus card which implements two full duplex Fibre Channel interfaces. Each Fibre Channel interface can connect to a Fibre Channel Arbitrated Loop (FC-AL). The socal device driver is a nexus driver and implements portions of the FC-2 and FC-4 layers of FC-AL. FILES
/kernel/drv/socal ELF Kernel Module ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Architecture |SPARC | +-----------------------------+-----------------------------+ SEE ALSO
sbus(4), sf(7D), ssd(7D) Writing Device Drivers ANSI X3.230-1994, Fibre Channel Physical and Signalling Interface (FC-PH) ANSI X3.272-1996, Fibre Channel Arbitrated Loop (FC-AL) Fibre Channel Private Loop SCSI Direct Attach (FC-PLDA) DIAGNOSTICS
The messages described below may appear on system console in addition to being logged. On the console, these messages are preceded by: socal%d: port %a where %d is the instance number of the socal controller and %a is the port on the host adapter. Fibre Channel Loop is ONLINE The Fibre Channel loop is now online. Fibre Channel Loop is OFFLINE The Fibre Channel loop is now offline. attach failed: device in slave-only slot. Move soc+ card to another slot. attach failed: bad soft state. Driver did not attach, devices will be inaccessible. attach failed: unable to alloc xport struct. Driver did not attach, devices will be inaccessible. attach failed: unable to map eeprom Driver was unable to map device memory; check for bad hardware. Driver did not attach to device, devices will be inaccessible. attach failed: unable to map XRAM Driver was unable to map device memory; check for bad hardware. Driver did not attach to device, devices will be inaccessible. attach failed: unable to map registers Driver was unable to map device registers; check for bad hardware. Driver did not attach to device, devices will be inaccessible. attach failed: unable to access status register Driver was unable to map device registers; check for bad hardware. Driver did not attach to device, devices will be inaccessible. attach failed: unable to install interrupt handler Driver was not able to add the interrupt routine to the kernel. Driver did not attach to device, devices will be inaccessible. attach failed: unable to access host adapter XRAM Driver was unable to access device RAM; check for bad hardware. Driver did not attach to device, devices will be inaccessible. attach failed: unable to write host adapter XRAM Driver was unable to write device RAM; check for bad hardware. Driver did not attach to device, devices will be inaccessible. attach failed: read/write mismatch in XRAM Driver was unable to verify device RAM; check for bad hardware. Driver did not attach to device, devices will be inaccessible. SunOS 5.10 9 May 1997 socal(7D)
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