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.
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.
(at the controller)
(at the controller)
(at the harddisk)
(at the harddisk)
34 PIN IDC MALE at the Controller.
20 PIN IDC MALE at the Controller.
34 PIN IDC FEMALE at the Harddisk.
20 PIN IDC FEMALE at the Harddisk.
| Pin | Name | Description |
|---|---|---|
| 2 | Head Sel 8 | |
| 4 | Head Sel 4 | |
| 6 | Write Gate | |
| 8 | Seek Complete | |
| 10 | Track 0 | |
| 12 | Write Fault | |
| 14 | Head Sel 1 | |
| 16 | RES | (reserved) |
| 18 | Head Sel 2 | |
| 20 | Index | |
| 22 | Ready | |
| 24 | Step | |
| 26 | Drive Sel 1 | |
| 28 | Drive Sel 2 | |
| 30 | Drive Sel 3 | |
| 32 | Drive Sel 4 | |
| 34 | Direction In |
Note: All odd pins are GND, Ground.
| Pin | Name | Description |
|---|---|---|
| 1 | Drive Selected | |
| 2 | GND | Ground |
| 3 | RES | (reserved) |
| 4 | GND | Ground |
| 5 | RES | (reserved) |
| 6 | GND | Ground |
| 7 | RES | (reserved) |
| 8 | GND | Ground |
| 9 | RES | (reserved) |
| 10 | RES | (reserved) |
| 11 | GND | Ground |
| 12 | GND | Ground |
| 13 | Write Data+ | |
| 14 | Write Data- | |
| 15 | GND | Ground |
| 16 | GND | Ground |
| 17 | Read Data+ | |
| 18 | Read Data- | |
| 19 | GND | Ground |
| 20 | GND | Ground |
| Contributor: | Joakim Ögren |
| Source: | ? |
Copyright © The Hardware Book Team 1996-2004.
May be copied and redistributed, partially or in whole, as appropriate.
Document last modified: 2002-01-10