SATA
Architectures
ST506/ST412 (Shugart)
Earliest interface for IBM XT. Supported 5/10 MB drives.
Used MFM/RLL encoding.
Drive dumb.
Drive control and data conversion on the interface card.
Separate cables for
control to c/h/s positioning electronics.
data (mfm tones) to record or read.
ESDI enhanced small disk interface (mid-90's).
Some of the drive control placed on the drive.
Supported other storage devices besides hard drives.
Eventually, it was realized it would be better to extend the
system bus via cabling to the hard drive's circuit board
and convert to mfm/rll there.
ATA - advanced technology attachement
- extends the AT(ISA) bus signal importatnt to hard drive.
IDE - integrated drive electronics
- places endec (encoder-decoder) and chs positioning on drive board.
Advantages of Integrated Drive Electronics (IDE)
IDE - control circuitry of a drive is placed on the drive rather than on
the host bus interface card.
Drive handles encoding, buffering, and signal conversions (endec).
Distance between encoded data and drive surface closer.
Drive electronics emulates drive configuration friendly to OS/Bios while
implementing suited for actual hardware design. Electronic lie to OS.
Magnetic storage is primarily an analog recording, analog data more
sensitive to corruption. digital to analog conversion done very close
to recording surface, limiting exposure.
Interface from cpu to drive does not change even if internals of drive do.
IDE interface for the PC AT - Integrated Drive Electronics
Correct name is ATA - AT attachement integrated drive interface. 1988
Primarily acts as an extention of the original PC/AT bus.
Extended the pins of the AT(ISA) bus onto cables that attached to the
hard drive and, later, CD/DVD/BluRay.
Hard drive controllers are memory mapped to specific addresses.
2 CS pins used to select command or control modules on controller
Indicates what data lines hold - control, address, data.
3 Address lines. Used to address ports in the command or control modules.
Hard drive controllers are memory mapped to specific addresses, so
data lines are not mulitplexed.
Used with CS lines to talk to control modules.
Control for hard drives mapped to certain locations in 1 Meg memory
range and decoded on interface card. This fine tuned sub-range.
Cable select.
Supports 2 drives on a single interface.
Master and Slave - arbitrary desigination for the two drives.
Drives recognize assignment.
Driver software "addresses" transaction and appropriate drive responds.
User has option of setting jumpers on drives to indicate address of drive
or use the cable wiring itself (cable select) to indicate address.
16 bit data bus. (Even with UDMA) 40 pin connector.
Data lines actually act as address, data, and command bus for accessing
data on device. (LBA, block read/write status, data transfer)
Reset, Ground, Power (although separate power also provided)
I/O handshaking.
Independent of system bus. So, you can use ide drives in non-Intel systems.
Initially asynchronous transfers between controller card on system and
controller chips on device.
Later went to a sychronous transfer for faster/more efficient transfers.
133MB/s max throughput.
2 drives per interface, 2 interfaces max per controller.
RAID 0 and 1
IDE interface - Integrated Drive Electronics
PIO and DMA modes.
Most of the control performed by the circuitry on the drive.
Hence the IDE assignation.
As AT-IDE evolved
CHS layout - some independence from OS/BIOS.
Supports drives up 528 MB (504MiB).
Still limited because total sector count had to jive with OS.
Finalized version
Supports up to 136.9 GB, although most system bioses could not.
Supports both chs and LBA 2^28-2^20 sectors.
Not all OSes or older BIOS supported LBA.
Newer protocol allows for a 48bit LBA counter.
ATA 1-3 has gone through a series of protocol updates.
Early versions coupled closely to IBM PC, AT bus, and OS/BIOS limits.
Eventually - LBA provided for more independence.
* Late 80's - AT bus disappearing, EISA (1988), MCA(1987), PCI (1992)
Faster bus 33MHz, DMA, Wider.
ATAPI - AT Attachment Packet Interface (mid-90s)
Additional protocols to allow use of "IDE" for CD-ROMs, Tape drives, etc.
Early CD-Roms controlled by sound card. (Custom)
ATA/ATAPI-4 - Improved DMA with on drive buffers. Improved throughput
from 16 MB/s to 33 MB/s
ATA/ATAPI-5
UDMA mode 4 provides for 66MB/s burst tranfers (hence mandatory cable).
80 connector cable became mandatory to reduce cross-talk at higher speeds.
Ground line between each active line.
Cable still has 40 pin connector and will work with older interface.
ATA/ATAPI-6
UDMA mode 5 up to 133 MB/s.
Expansion of the LBA count
Below ATA-6, 28 bit LBA storage or 137GB size barrier.
Should go up to 48 or 64 bit.
up to 144 PiB - petabyte - quadrillion - 1 thousand million million
Requires PC's BIOS to recognize it.
Many of these updates also require improvements in the interface card, system
BIOS and the OS to implement.
ATA-serial www.serialata.org
Standard ATA connector.
40 connector, 16 bit data path (16 bits synchronous).
12" (18" borderline) cable limit for good data transfers.
Additional 40 ground lines needed for faster protocols.
100MB/s practical limit. Some faster designs available.
ATA/ATAPI-7 - parallel.
UDMA Mode 6 - 133MBps. But near limit of disk drive response.
(Flash drives can respond faster to reads)
ATA-Serial (ATA/ATAPI-7)
Protocol follows standard ata design but the parallel cable is replaced
with a serial cable.
7 Connector
4 (2 lanes x 2 lines) signal and 3 ground
Point to point port of 2 paired lanes.
Data, address (lba, chs), and control use same lanes.
Interface controller converts normal parallel data to/from serial
bit stream encoded on 8b/10b RLL carrier.
Hard drive IDE circuit does same.
30" length safe. Max 39.37" (1 meter).
Single device - no master/slave hastles.
More detail on sata to follow.
System side controller protocol capable of 16 drives.
SATA/ATAPI-8
Removal of parallel protocol from standard.
Improved host protected area.
eSATA - external SATA.
More liberal signal protocol.
Cable up to 2M (6.6ft).
Most USB/Firewire external drives still S/PATA drive internally.
So, use of eSATA much faster.
Multiport interface (port multiplier)
Up to 15 SATA drives.
? 4 lanes (paired data lines)
Ide evolution 2
Lectures