Enhanced Small Device Interface. Disk drive interface introduced in the late 1980s that never really caught on. Had separate Cables for control and data, unlike SCSI and IDE, which use one cable for both. It came after IDE, and is not related to it.
Control cable pinout:
1
GNDGround
2
SH3Select Head 3
3
GNDGround
4
SH2Select Head 2
5
GNDGround
6
WWrite Gate
7
GNDGround
8
CONConfiguration Data
9
GNDGround
10
TACKTransfer Acknowledge
11
GNDGround
12
ATAttention
13
GNDGround
14
SH0Select Head 0
15
GNDGround
16
FOUNDSector Found
17
GNDGround
18
SH1Select Head 1
19
GNDGround
20
INDEXIndex
21
GNDGround
22
READYReady
23
GNDGround
24
TRQTransfer Request
25
GNDGround
26
SD1Select Drive 1
27
GNDGround
28
SD2Select Drive 2
29
GNDGround
30
SD3Select Drive 3
31
GNDGround
32
RRead gate
33
GNDGround
34
CDCommand Data
Data Connector:
1
DSDrive Selected
2
FOUNDSector Found
3
DONESeek Complete
4
AMEAddress Mark Enable
5
N/AReserved
6
GNDGround
7
WC+Write Clock +
8
WC-Write Clock -
9
CCCartridge Changed
10
RRC+Read Ref Clock +
11
RRC-Read Ref Clock -
12
GNDGround
13
NW+NRZ Write data +
14
NW-NRZ Write Data -
15
GNDGround
16
GNDGround
17
NR+NRZ Read data +
18
NR-NRZ Read data -
19
GNDGround
20
GNDGround