ST506/412 connector

#Computer#Harddisk interfaces

Developed by Seagate. Also known as MFM or RLL since these are the encoding methods used to store data. Seagate originally developed it to support their ST506 (5 MB) and ST412 (10 MB) drives.

34 pin IDC MALE connector pin-out & layout

34 pin IDC MALE connector  at the controller

The first drives used an encoding method called MFM (Modified Frequency Modulation). Later a new encoding method was developed, RLL (Run Length Limited). RLL had the advantage that it was possible to store 50% more with it. But it required better drives. This is almost never an problem. Often called 2,7 RLL because the recording scheme involves patterns with no more than 7 successive zeros and no less than two.

Second connector: 20 PIN IDC MALE at the Controller.
20 PIN IDC MALE

20 PIN IDC FEMALE at the Harddisk.
20 PIN IDC FEMALE

Control connector

PinNameDescription
2Head Sel 8
4Head Sel 4
6Write Gate
8Seek Complete
10Track 0
12Write Fault
14Head Sel 1
16RES(reserved)
18Head Sel 2
20Index
22Ready
24Step
26Drive Sel 1
28Drive Sel 2
30Drive Sel 3
32Drive Sel 4
34Direction In

Note: All odd pins are GND, Ground.

Data connector

PinNameDescription
1Drive Selected
2GNDGround
3RES(reserved)
4GNDGround
5RES(reserved)
6GNDGround
7RES(reserved)
8GNDGround
9RES(reserved)
10RES(reserved)
11GNDGround
12GNDGround
13Write Data+
14Write Data-
15GNDGround
16GNDGround
17Read Data+
18Read Data-
19GNDGround
20GNDGround

Spectravideo SVI318/328 Audio/Video connector

SUN Sparcstation 4, 5, 10, 20, LX, Classic, Classic X, Ultra Enterprise 450 Serial Port connector