44 pin Parallel ATA (IDE) pinout

44-pin connectors are mainly used in 2.5-inch PATA (IDE) hard drives for notebooks. They have the same pin assignment as the standard 40-pin PATA (IDE) connectors but there are 4 additional four pins (41 to 44) used for power supply. Another difference is that the spacing between pins is smaller due to the smaller drive size, which means that both interfaces are electrically, but not physically compatible. Therefore if you want to connect 44-pin drive to a 40-pin connector you will need a special adapter.

2.5 inch hard drives also have jumpers like their desktop counterparts but they are very rarely used, as in mobile computers hard drives are almost always configured to work as Master devices.
 

Pin	Signal	Description
1	/RESET	Reset
2	GND	Ground
3	DD7	Data 7
4	DD8	Data 8
5	DD6	Data 6
6	DD9	Data 9
7	DD5	Data 5
8	DD10	Data 10
9	DD4	Data 4
10	DD11	Data 11
11	DD3	Data 3
12	DD12	Data 12
13	DD2	Data 2
14	DD13	Data 13
15	DD1	Data 1
16	DD14	Data 14
17	DD0	Data 0
18	DD15	Data 15
19	GND	Ground
20	KEY	Key
21	n/c	Not connected
22	GND	Ground
23	/IOW	Write Strobe
24	GND	Ground
25	/IOR	Read Strobe
26	GND	Ground
27	IO_CH_RDY
28	ALE	Address Latch Enable
29	n/c	Not connected
30	GND	Ground
31	IRQR	Interrupt Request
32	/IOCS16	IO ChipSelect 16
33	DA1	Address 1
34	n/c	Not connected
35	DA0	Address 0
36	DA2	Address 2
37	/IDE_CS0	(1F0-1F7)
38	/IDE_CS1	(3F6-3F7)
39	/ACTIVE	Led driver
40	GND	Ground
41	+5VL	+5 VDC (Logic)
42	+5VM	+5 VDC (Motor)
43	GND	Ground
44	/TYPE	Type (0=ATA)