72-pin SIMM - Revision history

Eisapc at 07:43, 18 February 2020

2020-02-18T07:43:25Z

Eisapc at 10:53, 14 March 2018

2018-03-14T10:53:53Z

Eisapc: /* Non PC modules */

2018-03-13T22:04:03Z

‎Non PC modules

Eisapc: /* EOS-modules */

2018-03-13T21:49:10Z

‎EOS-modules

Eisapc: /* Parity modules */

2018-03-13T21:45:39Z

‎Parity modules

Eisapc: /* Parity modules */

2018-03-13T21:44:25Z

‎Parity modules

Eisapc: Created page with " 72-pin SIMM or as most people call it PS/2 SIMM, as it was first introduced with the IBM PS/2 line of personal computers, is the most common memory for late socket 4, socket..."

2018-03-13T21:04:30Z

Created page with " 72-pin SIMM or as most people call it PS/2 SIMM, as it was first introduced with the IBM PS/2 line of personal computers, is the most common memory for late socket 4, socket..."

New page

72-pin SIMM or as most people call it PS/2 SIMM, as it was first introduced with the IBM PS/2 line of personal computers, is the most common memory for late socket 4, socket 5, early socket 7 and socket 8 motherboards. It is used as add on memory in caching controllers or on soundcards like the Terratec EWS64 as well. The modules have 72 Pins and a data with of the modules is 32 bit witout and 36 bit with parity. While most Pentium class machines need the modules installed in pairs, 386er and 486er boards can use singel modules as well. 72-pin memory was superseded by 168-pin SDRAM.

72-pin SIMMs are availiable in the following capacities:
* 1 MB, 256 Kbit x 32/36 (rare)
* 2 MB, 512 KBIT x 32/36 (common in IBM PS/2)
* 4 MB, 1 Mbit x 32/36
* 8 MB, 2 MBIT x 32/36
* 16 MB 4 MBIT x 32/36
* 32 MB 8 MBIT x 32/36
* 64 MB 16 MBIT x 32/36 (rare, not supported on many motherboards)
* 128 MB 32 MBIT x 32/36 (rare, used on some hp 9000 workstations)

It first entered the market as Fast Page Mode (FPM). From 1995 on EDO memory modules were released which were 10 - 30 % faster but refuse to work in some older hardware. The difference can often be noticd fom the appendix on the memory chips or fom the chips partnunber itself. -70 ns chips and partnumbers ending on 0 like 5117400 are usually FPM.

==Parity modules==
Like 30-pin SIMMS before 72-pin SIMMS were availiable with and without parity. Vice versa from the 30-pin modules which usually came with parity, 72-pin SIMMs with parity are not very common. Quite a number of older Compaq and IBM or higher priced equipment like servers and workstations require parity modules installed. Parity modules can be easily detected as they usually cary extra chips. While non parity modules use 2, 4, 8 or 16 chips, parity modules have 3, 6, 9, 10, 18 or 20 chips.

==EOS-modules==
For some high priced servers from IBM and hp EOS-modules were availiable. These were sometimes advertised as ECC managleble SIMM, while EOS means ECC on chip. These modules can be easily recognized by the square chips on the modules.

==Presence detect==
72-pin modules have four pins used for presence detection. While these are not commonly used namely IBM made heavy use of them. Presence detect can easily modified with minor soldering skills.

==Non PC modules==
Some manufacturers of non x86 workstation released 72pin SIMMs not compatile with PCs. Notably IBM made some 40 Bit SIMMs for their RS/6000 line and hp modules from hp 9000 series are not compatible with PC-hardware.

=Sources=
*[Upgrading and Repairing PCs by Scott Mueller published 2001 (German edition)]
*[http://mcamafia.de/mcapage0/memorypd.htm Microchannel Mafia site on Presence Detect]
[[Category:Memory]]

← Older revision		Revision as of 07:43, 18 February 2020
Line 1:		Line 1:

−	72-pin SIMM or as most people call it PS/2 SIMM, as it was first introduced with the IBM PS/2 line of personal computers, is the most common memory for late socket 4, socket 5, early socket 7 and socket 8 motherboards. It is used as add on memory in caching controllers or on soundcards like the Terratec EWS64 as well. The modules have 72 Pins and a data with of the modules is 32 bit ~~witout~~ and 36 bit with parity. While most Pentium class machines need the modules installed in pairs, 386er and 486er boards can use ~~singel~~ modules as well. 72-pin memory was superseded by 168-pin SDRAM.	+	72-pin SIMM or as most people call it PS/2 SIMM, as it was first introduced with the IBM PS/2 line of personal computers, is the most common memory for late socket 4, socket 5, early socket 7 and socket 8 motherboards. It is used as add on memory in caching controllers or on soundcards like the Terratec EWS64 as well. The modules have 72 Pins and a data with of the modules is 32 bit without and 36 bit with parity. While most Pentium class machines need the modules installed in pairs, 386er and 486er boards can use single modules as well. 72-pin memory was superseded by 168-pin SDRAM.

	72-pin SIMMs are availiable in the following capacities:		72-pin SIMMs are availiable in the following capacities:

← Older revision		Revision as of 21:49, 13 March 2018
Line 19:		Line 19:

	==EOS-modules==		==EOS-modules==
		+	[[File:32MB_eos.jpg\|200px\|thumb\|A pair of 32 MB EOS modules]]
	For some high priced servers from IBM and hp EOS-modules were availiable. These were sometimes advertised as ECC managleble SIMM, while EOS means ECC on chip. These modules can be easily recognized by the square chips on the modules.		For some high priced servers from IBM and hp EOS-modules were availiable. These were sometimes advertised as ECC managleble SIMM, while EOS means ECC on chip. These modules can be easily recognized by the square chips on the modules.

@@ Line 15: / Line 15: @@
 ==Parity modules==
-[[File:16mb_parity.jpg|200px|thumb|A pair of 16 MB PS/2 SIMMs with parity]]
+[[File:16mb_parity.jpg|200px|thumb|A pair of 16 MB PS/2 SIMM modules with parity]]
 Like 30-pin SIMMS before 72-pin SIMMS were availiable with and without parity. Vice versa from the 30-pin modules which usually came with parity, 72-pin SIMMs with parity are not very common. Quite a number of older Compaq and IBM or higher priced equipment like servers and workstations require parity modules installed. Parity modules can be easily detected as they usually cary extra chips. While non parity modules use 2, 4, 8 or 16 chips, parity modules have 3, 6, 9, 10, 18 or 20 chips.

← Older revision		Revision as of 21:44, 13 March 2018
Line 15:		Line 15:

	==Parity modules==		==Parity modules==
		+	[[File:16mb_parity.jpg\|200px\|thumb\|A pair of 16 MB PS/2 SIMMs with parity]]
	Like 30-pin SIMMS before 72-pin SIMMS were availiable with and without parity. Vice versa from the 30-pin modules which usually came with parity, 72-pin SIMMs with parity are not very common. Quite a number of older Compaq and IBM or higher priced equipment like servers and workstations require parity modules installed. Parity modules can be easily detected as they usually cary extra chips. While non parity modules use 2, 4, 8 or 16 chips, parity modules have 3, 6, 9, 10, 18 or 20 chips.		Like 30-pin SIMMS before 72-pin SIMMS were availiable with and without parity. Vice versa from the 30-pin modules which usually came with parity, 72-pin SIMMs with parity are not very common. Quite a number of older Compaq and IBM or higher priced equipment like servers and workstations require parity modules installed. Parity modules can be easily detected as they usually cary extra chips. While non parity modules use 2, 4, 8 or 16 chips, parity modules have 3, 6, 9, 10, 18 or 20 chips.

@@ Line 15: / Line 15: @@
 ==Parity modules==
-[[File:16mb_parity.jpg|200px|thumb|A pair of 16 MB PS/2 SIMM modules with parity]]
+[[File:16mb_parity.jpg|200px|thumb|A pair of 16 MB PS/2 SIMM modules with parity. The resistors required for presence detect are in the upper right corner.]]
 Like 30-pin SIMMS before 72-pin SIMMS were availiable with and without parity. Vice versa from the 30-pin modules which usually came with parity, 72-pin SIMMs with parity are not very common. Quite a number of older Compaq and IBM or higher priced equipment like servers and workstations require parity modules installed. Parity modules can be easily detected as they usually cary extra chips. While non parity modules use 2, 4, 8 or 16 chips, parity modules have 3, 6, 9, 10, 18 or 20 chips.
@@ Line 23: / Line 23: @@
 ==Presence detect==
--pin modules have four pins used for presence detection. While these are not commonly used namely IBM made heavy use of them.  Presence detect can easily modified with minor soldering skills.
+-pin modules have four pins used for presence detection. Tis ment the board can detect size and speed of the memory module installed by evaluating the 4 presence detect pins. While these are not commonly used by most motherboard manufacturers namely IBM made heavy use of them.  Presence detect can easily modified with minor soldering skills.
 ==Non PC modules==

@@ Line 26: / Line 26: @@
 ==Non PC modules==
-Some manufacturers of non x86 workstation released 72pin SIMMs not compatile with PCs. Notably IBM made some 40 Bit SIMMs for their RS/6000 line and hp modules from hp 9000 series are not compatible with PC-hardware.
+[[File:hp9000_memory.jpg|200px|thumb|A pair modules from a hp 9000 PA-RISC workstation]]
 =Sources=