大多數情況下你可以從bios、産品目錄或者幹脆手動找出你的系統所持的最大記憶體。這裡，我們介紹一種簡單有用的技巧——使用dmidecode來找出系統支援的最大記憶體，這樣你就無需打開機箱或者參照bios和産品目錄了。
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就像你可能知道的一樣， dmidecode是一個将計算機dmi（又名smbios）表的内容轉換為可讀格式的工具。這個表包含了系統硬體元件的介紹以及其他一些如序列号和ios版本等有用的資訊。使用dmidecode你能夠擷取此項資訊，而無需去探測真實的硬體。
請确定你已經在系統中安裝了dmidecode，我覺得你的作業系統應該已經自動安裝過了，不過并不非常确定。
在基于deb的系統中安裝
<code>sudo apt-get install dmidecode</code>
在基于rpm的系統中安裝
<code>sudo yum install dmidecode</code>
在suse/opensuse中安裝
<code>sudo zypper in dmidecode</code>
好了，我們已經安裝了dmidecode，接下來讓我們找出支援的最大記憶體。輸入以下指令：
<code>sudo dmidecode -t 16</code>
輸出樣本
<code># dmidecode 2.12</code>
<code>smbios 2.6 present.</code>
<code></code>
<code>handle 0x0014, dmi type 16, 15 bytes</code>
<code>physical memory array</code>
<code>location: system board or motherboard</code>
<code>use: system memory</code>
<code>error correction type: none</code>
<code>maximum capacity: 16 gb</code>
<code>error information handle: not provided</code>
<code>number of devices: 2</code>
就像你看到的，我的系統支援最大記憶體到16g，并且有兩個記憶體插槽，簡單吧？
接下來，讓我們找出現在已經安裝的記憶體的詳細資訊。
<code>sudo dmidecode -t 17</code>
<code>handle 0x0017, dmi type 17, 28 bytes</code>
<code>memory device</code>
<code>array handle: 0x0014</code>
<code>error information handle: 0x0000</code>
<code>total width: unknown</code>
<code>data width: unknown</code>
<code>size: no module installed</code>
<code>form factor: dimm</code>
<code>set: none</code>
<code>locator: dimm_b</code>
<code>bank locator: bank 2</code>
<code>type: unknown</code>
<code>type detail: none</code>
<code>speed: unknown</code>
<code>manufacturer: not specified</code>
<code>serial number: not specified</code>
<code>asset tag: not specified</code>
<code>part number: not specified</code>
<code>rank: unknown</code>
<code>handle 0x0015, dmi type 17, 28 bytes</code>
<code>total width: 64 bits</code>
<code>data width: 64 bits</code>
<code>size: 4096 mb</code>
<code>form factor: sodimm</code>
<code>locator: dimm_a</code>
<code>bank locator: bank 0</code>
<code>type: ddr3</code>
<code>type detail: synchronous</code>
<code>speed: 1067 mhz</code>
<code>manufacturer: 014f</code>
<code>serial number: 00092af2</code>
<code>asset tag: 54114000</code>
<code>part number: jm1066ksn-4g</code>
就像上邊輸出的一樣，我在插槽1裡邊安裝了一個記憶體條。記憶體大小為4g，類型為ddr3，速度為1067 mhz。
同樣的，我們可以通過下邊指令得到完整的記憶體資訊。
<code>sudo dmidecode -t memory</code>
<code>sudo dmidecode -t memory | less</code>
<code>sudo dmidecode -t memory | more</code>
如果你好奇想要知道整個系統的詳細資訊，例如主機闆、記憶體、bios等，那麼可以輸入以下指令來擷取。
<code>48 structures occupying 2173 bytes.</code>
<code>table at 0x000eb840.</code>
<code>handle 0xda00, dmi type 218, 251 bytes</code>
<code>oem-specific type</code>
<code>header and data:</code>
<code>da fb 00 da b2 00 0d 5f 0f 37 40 7d 00 00 00 00</code>
<code>00 7e 00 01 00 00 00 dc 01 00 80 02 00 dd 01 00</code>
<code>80 03 00 75 01 01 80 01 00 76 01 02 80 01 00 2d</code>
<code>01 03 80 01 00 2e 01 03 80 00 00 81 01 07 80 00</code>
<code>00 82 01 07 80 01 00 83 01 08 80 00 00 84 01 08</code>
<code>80 01 00 85 01 06 80 00 00 86 01 06 80 01 00 58</code>
<code>02 05 80 00 00 57 02 05 80 01 00 9c 00 02 00 01</code>
<code>00 9b 00 02 00 00 00 8a 01 03 00 01 00 89 01 03</code>
<code>00 00 00 7f 01 04 00 00 00 80 01 04 00 01 00 53</code>
<code>01 05 00 00 00 52 01 05 00 01 00 7b 01 06 00 00</code>
<code>00 7c 01 06 00 01 00 94 01 07 00 00 00 93 01 07</code>
<code>00 01 00 7d 00 08 00 00 00 2d 00 09 00 01 00 2e</code>
<code>00 09 00 00 00 6e 00 0a 00 00 00 95 00 0b 00 01</code>
<code>00 96 00 0b 00 00 00 2f 02 0c 00 01 00 30 02 0c</code>
<code>00 00 00 50 02 0d 00 00 00 51 02 0d 00 01 00 52</code>
<code>02 0d 00 02 00 ff ff 00 00 00 00</code>
<code>handle 0xda01, dmi type 218, 59 bytes</code>
<code>da 3b 01 da b2 00 0d 5f 0f 37 40 53 02 0d 00 03</code>
<code>00 54 02 0d 00 04 00 56 02 0d 00 05 00 4b 01 0e</code>
<code>00 01 00 4a 01 0e 00 00 00 ea 00 0f 00 01 00 eb</code>
<code>00 0f 00 00 00 ff ff 00 00 00 00</code>
<code>handle 0x0004, dmi type 4, 42 bytes</code>
<code>processor information</code>
<code>socket designation: cpu 1</code>
<code>type: central processor</code>
<code>family: core i3</code>
<code>manufacturer: intel</code>
<code>id: a7 06 03 01 ff fb ab be</code>
<code>signature: type 0, family 6, model 42, stepping 7</code>
<code>flags:</code>
<code>fpu (floating-point unit on-chip)</code>
<code>vme (virtual mode extension)</code>
<code>de (debugging extension)</code>
<code>pse (page size extension)</code>
<code>tsc (time stamp counter)</code>
<code>msr (model specific registers)</code>
<code>pae (physical address extension)</code>
<code>mce (machine check exception)</code>
<code>cx8 (cmpxchg8 instruction supported)</code>
<code>apic (on-chip apic hardware supported)</code>
<code>sep (fast system call)</code>
<code>mtrr (memory type range registers)</code>
<code>pge (page global enable)</code>
<code>mca (machine check architecture)</code>
<code>cmov (conditional move instruction supported)</code>
<code>pat (page attribute table)</code>
<code>pse-36 (36-bit page size extension)</code>
<code>clfsh (clflush instruction supported)</code>
<code>ds (debug store)</code>
<code>acpi (acpi supported)</code>
<code>mmx (mmx technology supported)</code>
<code>fxsr (fxsave and fxstor instructions supported)</code>
<code>sse (streaming simd extensions)</code>
<code>sse2 (streaming simd extensions 2)</code>
<code>ss (self-snoop)</code>
<code>htt (multi-threading)</code>
<code>tm (thermal monitor supported)</code>
<code>pbe (pending break enabled)</code>
<code>version: intel(r) core(tm) i3-2350m cpu @ 2.30ghz</code>
<code>voltage: 1.1 v</code>
<code>external clock: 100 mhz</code>
<code>max speed: 2300 mhz</code>
<code>current speed: 2300 mhz</code>
<code>status: populated, enabled</code>
<code>upgrade: other</code>
<code>l1 cache handle: 0x0005</code>
<code>l2 cache handle: 0x0006</code>
<code>l3 cache handle: 0x0007</code>
<code>serial number: to be filled by o.e.m.</code>
<code>asset tag: to be filled by o.e.m.</code>
<code>part number: to be filled by o.e.m.</code>
<code>core count: 2</code>
<code>core enabled: 1</code>
<code>thread count: 2</code>
<code>characteristics:</code>
<code>64-bit capable</code>
<code>handle 0x0005, dmi type 7, 19 bytes</code>
<code>cache information</code>
<code>socket designation: l1-cache</code>
<code>configuration: enabled, not socketed, level 1</code>
<code>operational mode: write back</code>
<code>location: internal</code>
<code>installed size: 64 kb</code>
<code>maximum size: 64 kb</code>
<code>supported sram types:</code>
<code>other</code>
<code>installed sram type: other</code>
<code>system type: unified</code>
<code>associativity: 8-way set-associative</code>
<code>handle 0x0006, dmi type 7, 19 bytes</code>
<code>socket designation: l2-cache</code>
<code>configuration: enabled, not socketed, level 2</code>
<code>operational mode: varies with memory address</code>
<code>installed size: 512 kb</code>
<code>maximum size: 512 kb</code>
<code>handle 0x0007, dmi type 7, 19 bytes</code>
<code>socket designation: l3-cache</code>
<code>configuration: enabled, not socketed, level 3</code>
<code>installed size: 3072 kb</code>
<code>maximum size: 3072 kb</code>
<code>associativity: other</code>
<code>handle 0x0008, dmi type 8, 9 bytes</code>
<code>port connector information</code>
<code>internal reference designator: j1a1</code>
<code>internal connector type: none</code>
<code>external reference designator: ps2mouse</code>
<code>external connector type: ps/2</code>
<code>port type: mouse port</code>
<code>handle 0x0009, dmi type 8, 9 bytes</code>
<code>external reference designator: keyboard</code>
<code>port type: keyboard port</code>
<code>handle 0x000a, dmi type 8, 9 bytes</code>
<code>internal reference designator: j2a2b</code>
<code>external reference designator: video</code>
<code>external connector type: db-15 female</code>
<code>port type: video port</code>
<code>handle 0x000b, dmi type 8, 9 bytes</code>
<code>internal reference designator: j3a1</code>
<code>external reference designator: usb1</code>
<code>external connector type: access bus (usb)</code>
<code>port type: usb</code>
<code>handle 0x000c, dmi type 8, 9 bytes</code>
<code>external reference designator: usb2</code>
<code>handle 0x000d, dmi type 8, 9 bytes</code>
<code>external reference designator: usb3</code>
<code>handle 0x000e, dmi type 8, 9 bytes</code>
<code>internal reference designator: j5a1</code>
<code>external reference designator: lan</code>
<code>external connector type: rj-45</code>
<code>port type: network port</code>
<code>handle 0x000f, dmi type 9, 17 bytes</code>
<code>system slot information</code>
<code>designation: j6b2</code>
<code>type: x16 pci express</code>
<code>current usage: in use</code>
<code>length: long</code>
<code>id: 0</code>
<code>3.3 v is provided</code>
<code>opening is shared</code>
<code>pme signal is supported</code>
<code>bus address: 0000:00:01.0</code>
<code>handle 0x0010, dmi type 9, 17 bytes</code>
<code>designation: j6b1</code>
<code>type: x1 pci express</code>
<code>length: short</code>
<code>id: 1</code>
<code>bus address: 0000:00:1c.3</code>
<code>handle 0x0012, dmi type 11, 5 bytes</code>
<code>oem strings</code>
<code>string 1: dell system</code>
<code>string 2: 5[0003]</code>
<code>string 3: 13[p18f]</code>
<code>handle 0x0013, dmi type 12, 5 bytes</code>
<code>system configuration options</code>
<code>option 1: to be filled by o.e.m.</code>
<code>handle 0x001c, dmi type 21, 7 bytes</code>
<code>built-in pointing device</code>
<code>type: touch pad</code>
<code>interface: bus mouse</code>
<code>buttons: 2</code>
<code>handle 0x001d, dmi type 22, 26 bytes</code>
<code>portable battery</code>
<code>location: sys. battery bay</code>
<code>manufacturer: sanyo</code>
<code>serial number: 5390</code>
<code>name: dell 4yrjh22</code>
<code>chemistry: lithium ion</code>
<code>design capacity: 45000 mwh</code>
<code>design voltage: 10800 mv</code>
<code>sbds version: 1.0</code>
<code>maximum error: 2%</code>
<code>sbds manufacture date: 2012-02-28</code>
<code>oem-specific information: 0x00000001</code>
<code>handle 0x001e, dmi type 32, 20 bytes</code>
<code>system boot information</code>
<code>status: no errors detected</code>
<code>handle 0x0020, dmi type 27, 12 bytes</code>
<code>cooling device</code>
<code>type: fan</code>
<code>status: ok</code>
<code>oem-specific information: 0x00000000</code>
<code>handle 0x0021, dmi type 28, 20 bytes</code>
<code>temperature probe</code>
<code>description: cpu internal temperature</code>
<code>location: processor</code>
<code>maximum value: 127.0 deg c</code>
<code>minimum value: 0.0 deg c</code>
<code>resolution: 1.000 deg c</code>
<code>tolerance: 0.5 deg c</code>
<code>accuracy: unknown</code>
<code>handle 0xb000, dmi type 176, 5 bytes</code>
<code>b0 05 00 b0 00</code>
<code>handle 0xb100, dmi type 177, 12 bytes</code>
<code>b1 0c 00 b1 1a 0e 00 00 00 00 00 00</code>
<code>handle 0x0025, dmi type 209, 12 bytes</code>
<code>d1 0c 25 00 00 00 00 03 05 01 00 03</code>
<code>handle 0x0026, dmi type 210, 12 bytes</code>
<code>d2 0c 26 00 00 00 00 03 05 20 01 03</code>
<code>handle 0x0027, dmi type 211, 13 bytes</code>
<code>d3 0d 27 00 01 00 00 00 00 02 03 04 04</code>
<code>strings:</code>
<code>front</code>
<code>handle 0x0028, dmi type 212, 57 bytes</code>
<code>d4 39 28 00 70 00 71 00 01 49 50 48 9c 00 49 fc</code>
<code>01 9b 00 49 fc 00 7f 01 4a fb 04 80 01 4a fb 00</code>
<code>53 01 4a f7 08 52 01 4a f7 08 7b 01 4a ef 10 7c</code>
<code>01 4a ef 10 ff ff 00 00 00</code>
<code>handle 0x002a, dmi type 217, 8 bytes</code>
<code>d9 08 2a 00 01 02 00 00</code>
<code>handle 0x002b, dmi type 219, 11 bytes</code>
<code>db 0b 2b 00 00 01 02 03 00 04 05</code>
<code>handle 0x002c, dmi type 220, 22 bytes</code>
<code>dc 16 2c 00 01 f0 00 00 02 f0 00 00 00 00 03 f0</code>
<code>04 f0 00 00 00 00</code>
<code>handle 0x002d, dmi type 221, 19 bytes</code>
<code>dd 13 2d 00 00 00 00 00 00 03 00 00 00 00 00 00</code>
<code>00 00 00</code>
<code>handle 0x002e, dmi type 222, 16 bytes</code>
<code>de 10 2e 00 01 08 ff ff 00 00 00 00 00 00 00 00</code>
<code>handle 0x0016, dmi type 20, 19 bytes</code>
<code>memory device mapped address</code>
<code>starting address: 0x00000000000</code>
<code>ending address: 0x000ffffffff</code>
<code>range size: 4 gb</code>
<code>physical device handle: 0x0015</code>
<code>memory array mapped address handle: 0x0018</code>
<code>partition row position: 1</code>
<code>interleave position: 1</code>
<code>interleaved data depth: 1</code>
<code>handle 0x0018, dmi type 19, 15 bytes</code>
<code>memory array mapped address</code>
<code>physical array handle: 0x0014</code>
<code>partition width: 2</code>
<code>handle 0x002f, dmi type 13, 22 bytes</code>
<code>bios language information</code>
<code>language description format: abbreviated</code>
<code>installable languages: 1</code>
<code>eng</code>
<code>currently installed language: eng</code>
<code>handle 0x0030, dmi type 131, 64 bytes</code>
<code>83 40 30 00 31 00 00 00 00 00 00 00 00 00 00 00</code>
<code>f8 00 4b 1c ff ff ff ff 01 00 00 00 00 00 07 00</code>
<code>ad 04 04 00 00 00 00 00 c8 00 ff ff 00 00 00 00</code>
<code>00 00 00 00 32 00 00 00 76 50 72 6f 00 00 00 00</code>
<code>handle 0x0029, dmi type 216, 9 bytes</code>
<code>d8 09 29 00 01 02 01 00 00</code>
<code>intel</code>
<code>0000</code>
<code>handle 0x0000, dmi type 0, 24 bytes</code>
<code>bios information</code>
<code>vendor: dell inc.</code>
<code>version: a05</code>
<code>release date: 08/03/2012</code>
<code>address: 0xf0000</code>
<code>runtime size: 64 kb</code>
<code>rom size: 2048 kb</code>
<code>mca is supported</code>
<code>pci is supported</code>
<code>bios is upgradeable</code>
<code>bios shadowing is allowed</code>
<code>escd support is available</code>
<code>boot from cd is supported</code>
<code>selectable boot is supported</code>
<code>bios rom is socketed</code>
<code>edd is supported</code>
<code>5.25"/1.2 mb floppy services are supported (int 13h)</code>
<code>3.5"/720 kb floppy services are supported (int 13h)</code>
<code>3.5"/2.88 mb floppy services are supported (int 13h)</code>
<code>print screen service is supported (int 5h)</code>
<code>8042 keyboard services are supported (int 9h)</code>
<code>serial services are supported (int 14h)</code>
<code>printer services are supported (int 17h)</code>
<code>cga/mono video services are supported (int 10h)</code>
<code>acpi is supported</code>
<code>usb legacy is supported</code>
<code>atapi zip drive boot is supported</code>
<code>bios boot specification is supported</code>
<code>targeted content distribution is supported</code>
<code>bios revision: 0.5</code>
<code>firmware revision: 0.5</code>
<code>handle 0x0002, dmi type 2, 15 bytes</code>
<code>base board information</code>
<code>manufacturer: dell inc.</code>
<code>product name: 01hxxj</code>
<code>serial number: .jsq7pa1.cn7117623m00j2.</code>
<code>features:</code>
<code>board is a hosting board</code>
<code>board is replaceable</code>
<code>location in chassis: to be filled by o.e.m.</code>
<code>chassis handle: 0x0003</code>
<code>type: motherboard</code>
<code>contained object handles: 0</code>
<code>handle 0x0003, dmi type 3, 21 bytes</code>
<code>chassis information</code>
<code>type: portable</code>
<code>lock: not present</code>
<code>version: not specified</code>
<code>serial number: jsr1</code>
<code>boot-up state: safe</code>
<code>power supply state: safe</code>
<code>thermal state: safe</code>
<code>security status: none</code>
<code>oem information: 0x00000000</code>
<code>height: unspecified</code>
<code>number of power cords: 1</code>
<code>contained elements: 0</code>
<code>handle 0x0001, dmi type 1, 27 bytes</code>
<code>system information</code>
<code>product name: inspiron n5050</code>
<code>uuid: 4c4c4544-0053-5110-8029-cac05241</code>
<code>wake-up type: power switch</code>
<code>sku number: to be filled by o.e.m.</code>
<code>family:</code>
<code>handle 0x0024, dmi type 208, 12 bytes</code>
<code>d0 0c 24 00 02 05 fe 00 04 05 01 02</code>
<code>20120323</code>
<code>handle 0x0011, dmi type 10, 6 bytes</code>
<code>on board device information</code>
<code>type: video</code>
<code>status: enabled</code>
<code>description: mobile intel sandybridge hd graphics</code>
<code>serial number: 0009f2</code>
<code>part number: jm1066-4g</code>
<code>handle 0x0031, dmi type 127, 4 bytes</code>
<code>end of table</code>
好了，就是這樣。
原文釋出時間：2015-03-31
本文來自雲栖合作夥伴“linux中國”
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