Real Mode OS Warning: Difference between revisions

← Older edit

Real Mode OS Warning (view source)

Revision as of 07:29, 10 September 2020

380 bytes added , 3 years ago

m

Fixed spelling

[unchecked revision]

VisualWikitext

Anonymous user

osdev>A22347

Revision as of 22:59, 9 September 2018 (view source) osdev>Carver No edit summary ← Older edit		Latest revision as of 07:29, 10 September 2020 (view source) osdev>A22347 m (Fixed spelling)
(2 intermediate revisions by 2 users not shown)
Line 7: Currently the entire industry (all "80x86 PC" manufacturers all OSs for "80x86 PC") are shifting to UEFI. At the end of this transition (at some point in the future) BIOS will cease to exist. Relying on the existence of BIOS functions is not a long term option. Temporarily relying on the existence of BIOS functions (for the short term) makes it much much harder to port the OS to UEFI later, and also makes it much much harder to port the OS to other platforms (ARM, SPARC, etc) because everything that the BIOS was used for has to be replaced. ''Note: Intel has officially stated that they will cease supporting BIOS (go from "BIOS+UEFI hybrid" to "UEFI only") before the year 2020; and some people expect that Intel's main reason for doing this is so that they can start removing obsolete hardware from their chipsets (starting with A20 gate, and possibly including PIC, PIT, PS/2, legacy ROM areas and VGA emulation).'' == BIOS Does Not Support All Devices == Line 42 ⟶ 44: For hot-plug devices (all SATA disks, all USB devices, etc) there is no support for hot-plug. E.g. if the user unplugs a USB flash device (or SATA hard drive or...) there's no notification (read/writes to the device simply cause an error) and if the user plugs in a USB flash device (or SATA hard drive or...) there's no way for the OS to use it (the BIOS continues to pretend the device doesn't exist). There is no concept of IO priorities and no way to cancel an "in progress" transfer. This means that if you need to ~~tansfer~~transfer data as soon as possible then that transfer has to wait until any less important "in progress" transfer completes. There is no support for "trim" (for SSD and USB flash), no support for "secure erase", no support for "eject" (for CD drives), no support for monitoring the health of the device ("Self-Monitoring, Analysis and Reporting Technology"), no support for hard drives with 4 KiB sectors (determining if the drive has 4 KiB sectors or not), and no support for "write barriers" or determining if the data has actually been written to the media and not just buffered by the drive (needed to ensure power failures can't cause file system corruption).