Programmed input–output: Difference between revisions

Revision as of 20:25, 4 December 2018

Revision as of 21:21, 4 December 2018

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=== PIO Mode 5 ===

A PIO Mode 5 was proposed<ref name="ATA Timing Extension For ATA-3">''Proposed 22 MByte/Sec ATA Timing Extension For ATA-3, January 1995, [ftp://ftp.t10.org/t10/document.95/95-122r0.pdf ATA-3 Extension Proposal]{{dead link|date=April 2018 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> with operation at 22 MB/s, but was never implemented on hard disks because CPUs of the time would have been crippled waiting for the hard disk at the proposed PIO 5 timings, and the [[Direct memory access|DMA]] standard ultimately obviated it. While no [[Hard disk|hard drives]] were ever manufactured to support this mode, some [[motherboard]] manufacturers preemptively provided [[BIOS]] support for it. PIO Mode 5 can be used with CompactFlash cards connected to IDE via CF-to-IDE adapters.

=== Device compatibility ===

Not all devices are compatible with the official PIO timings. An example is the Sandisk SDDR-89 ImageMate 12-in-1 card reader which uses the GL819 chip from [[Genesys Logic, Inc.]] That chip has slightly different timings for most of its PIO Modes.

{| class="wikitable" style="text-align:center"

|PIO Mode || 1 || 2 || 3 || 4 || 6

|-

| GL819 timings

| 399 [[1 E-9 s|ns]]

| 249 [[1 E-9 s|ns]]

| 183 [[1 E-9 s|ns]]

| 133 [[1 E-9 s|ns]]

| 83 [[1 E-9 s|ns]]

|-

| ATA & CF spec timings

| 383 [[1 E-9 s|ns]]

| 240 [[1 E-9 s|ns]]

| 180 [[1 E-9 s|ns]]

| 120 [[1 E-9 s|ns]]

| 80 [[1 E-9 s|ns]]

|}

== See also ==