IBM xSeries服务器安装内存一则

部门进购IBM xSeries 225服务器已经达三年之久了，128*2=256MB RAM + 40G HDD跑起来嘎哒嗄哒地响，期间一直没有更新过，如今赶上个好日子，领导重视服务器应用起来了，于是报告一批，一根512MB的内存条马上就到手了。

趁着这喜头，连夜加班装到机器上面，一开机却发现不了512M+256M那么多的内存，却只有640MB。郁闷，怎么会这样子呢？换个插槽试试，结果总共四个插槽和三根内存条，试遍了整整3*3*3*3种方法，却发现内存最大也只能为640MB，最小却有128MB，倒哦，白喜了一趟，那夜晚上就用了那640MB的内存一直跑到如今来了。

那是比较久的事了，大概还是半年前。嘿嘿，今天兴致比较好，居然又想动起这个来了，于是把它又整出来（IBM的机箱真难拆）。这一次换了思路了，打算先从文档下手，嘿嘿，找到了“@server xSeries 225 Documentation”这张光盘，放进去看一下文档，居然有“Installation Guide”，进去查找，找到了，现引用原文如下哦：

Installing memory modules
You can increase the amount of memory in your server by installing memory
modules. Your server uses industry-standard PC2100 double-data-rate (DDR) dual
inline memory modules (DIMMs).
Notes:
1. The system board contains four DIMM connectors and supports two-way
memory interleaving.
2. The DIMM options available for your server are 128 MB, 256 MB, 512 MB, 1
GB, and 2 GB. Your server supports a minimum of 256 MB and a maximum of 8
GB of system memory.
3. The amount of usable memory will be reduced depending on the system
configuration. A certain amount of memory must be reserved for system
resources. The BIOS will display the total amount of installed memory and the
amount of configured memory.
4. Your server comes with two 256 MB or 512 MB DIMMs (for a total of 512 MB or
1024 MB) installed in the DIMM 3 and DIMM 4 memory connectors. When you
install additional DIMMs, be sure to install them as a pair in DIMM connectors 1
and 2.
5. DIMMs must be installed in matched pairs. The first pair of DIMMs you install in
DIMM 3 and DIMM 4 memory connectors must be the same size, speed, type,
and technology. You can mix compatible DIMMs from various manufacturers. If
you install a second pair of DIMMs in DIMM 1 and DIMM 2 memory connectors,
they do not have to be the same size, speed, type, and technology as the
DIMMs you installed in DIMM 3 and DIMM 4 memory connectors. However, the
size, speed, type, and technology of the DIMMs you install in DIMM 1 and
DIMM 2 memory connectors must match each other.
6. Install only 133 MHz (memory bus), 2.5 V, 184-pin, double-data-rate (DDR),
PC2100, registered synchronous dynamic random-access memory (SDRAM)
with error correcting code (ECC) DIMMs. These DIMMs must be compatible
with the latest PC2100 SDRAM Registered DIMM specification. For a list of
supported options for your server, go to http://www.ibm.com/us/compat/ on the
World Wide Web.
7. Your server supports Chipkill™ memory if the DIMMs are all type x4 and are 256
MB or larger. Using any 128 MB DIMMs or DIMMs that are not type x4 on your
server disables Chipkill memory.
Complete the following steps to install a DIMM:
1. Review the safety information beginning on page vii, “Installation guidelines” on
page 9, and “Handling static-sensitive devices” on page 10.
2. Remove the side cover (see “Removing the side cover” on page 11).
3. Remove the support bracket (see “Removing and installing the support bracket”
on page 13).
4. Locate the DIMM connectors on the system board. Determine the connectors
into which you will install the DIMMs. Install the DIMMs in the order shown in
the following table.
Table 3. DIMM installation sequence
Installation order DIMM connectors Diagnostic reference
First DIMM 3 and DIMM 4 Bank 2
Second DIMM 1 and DIMM 2 Bank 1
28 IBM xSeries 225 Type 8647: Installation Guide
5. Open the retaining clips and, if necessary, remove any existing DIMM.
6. Touch the static-protective package containing the DIMM to any unpainted metal
surface on the server. Then remove the new DIMM from the package.
7. Gently open the retaining clip on each end of the DIMM slot. Turn the DIMM so
that the pins align correctly with the connector.
8. Insert the DIMM into the connector. Firmly press the DIMM straight down into
the connector by applying pressure on both ends of the DIMM simultaneously.
The retaining clips snap into the locked position when the DIMM is firmly seated
in the connector. If there is a gap between the DIMM and the retaining clips, the
DIMM has not been correctly installed. Open the retaining clips, remove the
DIMM, and then reinsert it.
DIMM 1
DIMM 3
DIMM 2
DIMM 4
9. If you have other options to install or remove, do so now; otherwise, replace the
support bracket (see “Removing and installing the support bracket” on page 13)
and go to “Completing the installation” on page 34.

看了上面的说明，大概就知道了真的不能这么混着插内存条的，必须成pairs出现的在DIMM1,DIMM2或DIMM3,DIMM4中。刚看完这个，就有点后悔为什么当初没有此东西了。唉！~