Linux基礎：如何找出你的系統所支持的最大內存

　　大多數情況下你可以從BIOS、產品目錄或者干脆手動找出你的系統所持的最大內存。這里，我們介紹一種簡單有用的技巧——使用dmidecode來找出系統支持的最大內存，這樣你就無需打開機箱或者參照BIOS和產品目錄了。讓我們一起去看看。

　　Linux基礎：如何找出你的系統所支持的最大內存：

　　什么是 dmidecode?

　　就像你可能知道的一樣， dmidecode是一個將計算機DMI(又名SMBIOS)表的內容轉換為可讀格式的工具。這個表包含了系統硬件組件的介紹以及其他一些如序列號和IOS版本等有用的信息。使用dmidecode你能夠獲取此項信息，而無需去探測真實的硬件。

　　找出你的系統所支持的最大內存

　　請確定你已經在系統中安裝了dmidecode，我覺得你的操作系統應該已經自動安裝過了，不過并不非常確定。

　　在基于Deb的系統中安裝

　　sudo apt-get install dmidecode

　　在基于RPM的系統中安裝

　　sudo yum install dmidecode

　　在SUSE/openSUSE中安裝

　　sudo zypper in dmidecode

　　好了，我們已經安裝了dmidecode，接下來讓我們找出支持的最大內存。輸入以下命令：

　　sudo dmidecode -t 16

　　輸出樣本

　　# dmidecode 2.12

　　SMBIOS 2.6 present.

　　Handle 0x0014, DMI type 16, 15 bytes

　　Physical Memory Array

　　Location: System Board Or Motherboard

　　Use: System Memory

　　Error Correction Type: None

　　Maximum Capacity: 16 GB

　　Error Information Handle: Not Provided

　　Number Of Devices: 2

　　就像你看到的，我的系統支持最大內存到16G，并且有兩個內存插槽，簡單吧?

　　接下來，讓我們找出現在已經安裝的內存的詳細信息。

　　sudo dmidecode -t 17

　　輸出樣本

　　# dmidecode 2.12

　　SMBIOS 2.6 present.

　　Handle 0x0017, DMI type 17, 28 bytes

　　Memory Device

　　Array Handle: 0x0014

　　Error Information Handle: 0x0000

　　Total Width: Unknown

　　Data Width: Unknown

　　Size: No Module Installed

　　Form Factor: DIMM

　　Set: None

　　Locator: DIMM_B

　　Bank Locator: BANK 2

　　Type: Unknown

　　Type Detail: None

　　Speed: Unknown

　　Manufacturer: Not Specified

　　Serial Number: Not Specified

　　Asset Tag: Not Specified

　　Part Number: Not Specified

　　Rank: Unknown

　　Handle 0x0015, DMI type 17, 28 bytes

　　Memory Device

　　Array Handle: 0x0014

　　Error Information Handle: 0x0000

　　Total Width: 64 bits

　　Data Width: 64 bits

　　Size: 4096 MB

　　Form Factor: SODIMM

　　Set: None

　　Locator: DIMM_A

　　Bank Locator: BANK 0

　　Type: DDR3

　　Type Detail: Synchronous

　　Speed: 1067 MHz

　　Manufacturer: 014F

　　Serial Number: 00092AF2

　　Asset Tag: 54114000

　　Part Number: JM1066KSN-4G

　　Rank: Unknown

　　就像上邊輸出的一樣，我在插槽1里邊安裝了一個內存條。內存大小為4G，類型為DDR3，速度為1067 MHz。

　　同樣的，我們可以通過下邊命令得到完整的內存信息。

　　sudo dmidecode -t memory

　　sudo dmidecode -t memory | less

　　sudo dmidecode -t memory | more

　　輸出樣本

　　# dmidecode 2.12

　　SMBIOS 2.6 present.

　　Handle 0x0014, DMI type 16, 15 bytes

　　Physical Memory Array

　　Location: System Board Or Motherboard

　　Use: System Memory

　　Error Correction Type: None

　　Maximum Capacity: 16 GB

　　Error Information Handle: Not Provided

　　Number Of Devices: 2

　　Handle 0x0017, DMI type 17, 28 bytes

　　Memory Device

　　Array Handle: 0x0014

　　Error Information Handle: 0x0000

　　Total Width: Unknown

　　Data Width: Unknown

　　Size: No Module Installed

　　Form Factor: DIMM

　　Set: None

　　Locator: DIMM_B

　　Bank Locator: BANK 2

　　Type: Unknown

　　Type Detail: None

　　Speed: Unknown

　　Manufacturer: Not Specified

　　Serial Number: Not Specified

　　Asset Tag: Not Specified

　　Part Number: Not Specified

　　Rank: Unknown

　　Handle 0x0015, DMI type 17, 28 bytes

　　Memory Device

　　Array Handle: 0x0014

　　Error Information Handle: 0x0000

　　Total Width: 64 bits

　　Data Width: 64 bits

　　Size: 4096 MB

　　Form Factor: SODIMM

　　Set: None

　　Locator: DIMM_A

　　Bank Locator: BANK 0

　　Type: DDR3

　　Type Detail: Synchronous

　　Speed: 1067 MHz

　　Manufacturer: 014F

　　Serial Number: 00092AF2

　　Asset Tag: 54114000

　　Part Number: JM1066KSN-4G

　　Rank: Unknown

　　如果你好奇想要知道整個系統的詳細信息，例如主板、內存、BIOS等，那么可以輸入以下命令來獲取。

　　sudo dmidecode

　　輸出樣本

　　# dmidecode 2.12

　　SMBIOS 2.6 present.

　　48 structures occupying 2173 bytes.

　　Table at 0x000EB840.

　　Handle 0xDA00, DMI type 218, 251 bytes

　　OEM-specific Type

　　Header and Data:

　　DA FB 00 DA B2 00 0D 5F 0F 37 40 7D 00 00 00 00

　　00 7E 00 01 00 00 00 DC 01 00 80 02 00 DD 01 00

　　80 03 00 75 01 01 80 01 00 76 01 02 80 01 00 2D

　　01 03 80 01 00 2E 01 03 80 00 00 81 01 07 80 00

　　00 82 01 07 80 01 00 83 01 08 80 00 00 84 01 08

　　80 01 00 85 01 06 80 00 00 86 01 06 80 01 00 58

　　02 05 80 00 00 57 02 05 80 01 00 9C 00 02 00 01

　　00 9B 00 02 00 00 00 8A 01 03 00 01 00 89 01 03

　　00 00 00 7F 01 04 00 00 00 80 01 04 00 01 00 53

　　01 05 00 00 00 52 01 05 00 01 00 7B 01 06 00 00

　　00 7C 01 06 00 01 00 94 01 07 00 00 00 93 01 07

　　00 01 00 7D 00 08 00 00 00 2D 00 09 00 01 00 2E

　　00 09 00 00 00 6E 00 0A 00 00 00 95 00 0B 00 01

　　00 96 00 0B 00 00 00 2F 02 0C 00 01 00 30 02 0C

　　00 00 00 50 02 0D 00 00 00 51 02 0D 00 01 00 52

　　02 0D 00 02 00 FF FF 00 00 00 00

　　Handle 0xDA01, DMI type 218, 59 bytes

　　OEM-specific Type

　　Header and Data:

　　DA 3B 01 DA B2 00 0D 5F 0F 37 40 53 02 0D 00 03

　　00 54 02 0D 00 04 00 56 02 0D 00 05 00 4B 01 0E

　　00 01 00 4A 01 0E 00 00 00 EA 00 0F 00 01 00 EB

　　00 0F 00 00 00 FF FF 00 00 00 00

　　Handle 0x0004, DMI type 4, 42 bytes

　　Processor Information

　　Socket Designation: CPU 1

　　Type: Central Processor

　　Family: Core i3

　　Manufacturer: Intel

　　ID: A7 06 03 01 FF FB AB BE

　　Signature: Type 0, Family 6, Model 42, Stepping 7

　　Flags:

　　FPU (Floating-point unit on-chip)

　　VME (Virtual mode extension)

　　DE (Debugging extension)

　　PSE (Page size extension)

　　TSC (Time stamp counter)

　　MSR (Model specific registers)

　　PAE (Physical address extension)

　　MCE (Machine check exception)

　　CX8 (CMPXCHG8 instruction supported)

　　APIC (On-chip APIC hardware supported)

　　SEP (Fast system call)

　　MTRR (Memory type range registers)

　　PGE (Page global enable)

　　MCA (Machine check architecture)

　　CMOV (Conditional move instruction supported)

　　PAT (Page attribute table)

　　PSE-36 (36-bit page size extension)

　　CLFSH (CLFLUSH instruction supported)

　　DS (Debug store)

　　ACPI (ACPI supported)

　　MMX (MMX technology supported)

　　FXSR (FXSAVE and FXSTOR instructions supported)

　　SSE (Streaming SIMD extensions)

　　SSE2 (Streaming SIMD extensions 2)

　　SS (Self-snoop)

　　HTT (Multi-threading)

　　TM (Thermal monitor supported)

　　PBE (Pending break enabled)

　　Version: Intel(R) Core(TM) i3-2350M CPU @ 2.30GHz

　　Voltage: 1.1 V

　　External Clock: 100 MHz

　　Max Speed: 2300 MHz

　　Current Speed: 2300 MHz

　　Status: Populated, Enabled

　　Upgrade: Other

　　L1 Cache Handle: 0x0005

　　L2 Cache Handle: 0x0006

　　L3 Cache Handle: 0x0007

　　Serial Number: To Be Filled By O.E.M.

　　Asset Tag: To Be Filled By O.E.M.

　　Part Number: To Be Filled By O.E.M.

　　Core Count: 2

　　Core Enabled: 1

　　Thread Count: 2

　　Characteristics:

　　64-bit capable

　　Handle 0x0005, DMI type 7, 19 bytes

　　Cache Information

　　Socket Designation: L1-Cache

　　Configuration: Enabled, Not Socketed, Level 1

　　Operational Mode: Write Back

　　Location: Internal

　　Installed Size: 64 kB

　　Maximum Size: 64 kB

　　Supported SRAM Types:

　　Other

　　Installed SRAM Type: Other

　　Speed: Unknown

　　Error Correction Type: None

　　System Type: Unified

　　Associativity: 8-way Set-associative

　　Handle 0x0006, DMI type 7, 19 bytes

　　Cache Information

　　Socket Designation: L2-Cache

　　Configuration: Enabled, Not Socketed, Level 2

　　Operational Mode: Varies With Memory Address

　　Location: Internal

　　Installed Size: 512 kB

　　Maximum Size: 512 kB

　　Supported SRAM Types:

　　Other

　　Installed SRAM Type: Other

　　Speed: Unknown

　　Error Correction Type: None

　　System Type: Unified

　　Associativity: 8-way Set-associative

　　Handle 0x0007, DMI type 7, 19 bytes

　　Cache Information

　　Socket Designation: L3-Cache

　　Configuration: Enabled, Not Socketed, Level 3

　　Operational Mode: Varies With Memory Address

　　Location: Internal

　　Installed Size: 3072 kB

　　Maximum Size: 3072 kB

　　Supported SRAM Types:

　　Other

　　Installed SRAM Type: Other

　　Speed: Unknown

　　Error Correction Type: None

　　System Type: Unified

　　Associativity: Other

　　Handle 0x0008, DMI type 8, 9 bytes

　　Port Connector Information

　　Internal Reference Designator: J1A1

　　Internal Connector Type: None

　　External Reference Designator: PS2Mouse

　　External Connector Type: PS/2

　　Port Type: Mouse Port

　　Handle 0x0009, DMI type 8, 9 bytes

　　Port Connector Information

　　Internal Reference Designator: J1A1

　　Internal Connector Type: None

　　External Reference Designator: Keyboard

　　External Connector Type: PS/2

　　Port Type: Keyboard Port

　　Handle 0x000A, DMI type 8, 9 bytes

　　Port Connector Information

　　Internal Reference Designator: J2A2B

　　Internal Connector Type: None

　　External Reference Designator: Video

　　External Connector Type: DB-15 female

　　Port Type: Video Port

　　Handle 0x000B, DMI type 8, 9 bytes

　　Port Connector Information

　　Internal Reference Designator: J3A1

　　Internal Connector Type: None

　　External Reference Designator: USB1

　　External Connector Type: Access Bus (USB)

　　Port Type: USB

　　Handle 0x000C, DMI type 8, 9 bytes

　　Port Connector Information

　　Internal Reference Designator: J3A1

　　Internal Connector Type: None

　　External Reference Designator: USB2

　　External Connector Type: Access Bus (USB)

　　Port Type: USB

　　Handle 0x000D, DMI type 8, 9 bytes

　　Port Connector Information

　　Internal Reference Designator: J3A1

　　Internal Connector Type: None

　　External Reference Designator: USB3

　　External Connector Type: Access Bus (USB)

　　Port Type: USB

　　Handle 0x000E, DMI type 8, 9 bytes

　　Port Connector Information

　　Internal Reference Designator: J5A1

　　Internal Connector Type: None

　　External Reference Designator: LAN

　　External Connector Type: RJ-45

　　Port Type: Network Port

　　Handle 0x000F, DMI type 9, 17 bytes

　　System Slot Information

　　Designation: J6B2

　　Type: x16 PCI Express

　　Current Usage: In Use

　　Length: Long

　　ID: 0

　　Characteristics:

　　3.3 V is provided

　　Opening is shared

　　PME signal is supported

　　Bus Address: 0000:00:01.0

　　Handle 0x0010, DMI type 9, 17 bytes

　　System Slot Information

　　Designation: J6B1

　　Type: x1 PCI Express

　　Current Usage: In Use

　　Length: Short

　　ID: 1

　　Characteristics:

　　3.3 V is provided

　　Opening is shared

　　PME signal is supported

　　Bus Address: 0000:00:1c.3

　　Handle 0x0012, DMI type 11, 5 bytes

　　OEM Strings

　　String 1: Dell System

　　String 2: 5[0003]

　　String 3: 13[P18F]

　　Handle 0x0013, DMI type 12, 5 bytes

　　System Configuration Options

　　Option 1: To Be Filled By O.E.M.

　　Handle 0x001C, DMI type 21, 7 bytes

　　Built-in Pointing Device

　　Type: Touch Pad

　　Interface: Bus Mouse

　　Buttons: 2

　　Handle 0x001D, DMI type 22, 26 bytes

　　Portable Battery

　　Location: Sys. Battery Bay

　　Manufacturer: Sanyo

　　Serial Number: 5390

　　Name: DELL 4YRJH22

　　Chemistry: Lithium Ion

　　Design Capacity: 45000 mWh

　　Design Voltage: 10800 mV

　　SBDS Version: 1.0

　　Maximum Error: 2%

　　SBDS Manufacture Date: 2012-02-28

　　OEM-specific Information: 0x00000001

　　Handle 0x001E, DMI type 32, 20 bytes

　　System Boot Information

　　Status: No errors detected

　　Handle 0x0020, DMI type 27, 12 bytes

　　Cooling Device

　　Type: Fan

　　Status: OK

　　OEM-specific Information: 0x00000000

　　Handle 0x0021, DMI type 28, 20 bytes

　　Temperature Probe

　　Description: CPU Internal Temperature

　　Location: Processor

　　Status: OK

　　Maximum Value: 127.0 deg C

　　Minimum Value: 0.0 deg C

　　Resolution: 1.000 deg C

　　Tolerance: 0.5 deg C

　　Accuracy: Unknown

　　OEM-specific Information: 0x00000000

　　Handle 0xB000, DMI type 176, 5 bytes

　　OEM-specific Type

　　Header and Data:

　　B0 05 00 B0 00

　　Handle 0xB100, DMI type 177, 12 bytes

　　OEM-specific Type

　　Header and Data:

　　B1 0C 00 B1 1A 0E 00 00 00 00 00 00

　　Handle 0x0025, DMI type 209, 12 bytes

　　OEM-specific Type

　　Header and Data:

　　D1 0C 25 00 00 00 00 03 05 01 00 03

　　Handle 0x0026, DMI type 210, 12 bytes

　　OEM-specific Type

　　Header and Data:

　　D2 0C 26 00 00 00 00 03 05 20 01 03

　　Handle 0x0027, DMI type 211, 13 bytes

　　OEM-specific Type

　　Header and Data:

　　D3 0D 27 00 01 00 00 00 00 02 03 04 04

　　Strings:

　　Front

　　Handle 0x0028, DMI type 212, 57 bytes

　　OEM-specific Type

　　Header and Data:

　　D4 39 28 00 70 00 71 00 01 49 50 48 9C 00 49 FC

　　01 9B 00 49 FC 00 7F 01 4A FB 04 80 01 4A FB 00

　　53 01 4A F7 08 52 01 4A F7 08 7B 01 4A EF 10 7C

　　01 4A EF 10 FF FF 00 00 00

　　Handle 0x002A, DMI type 217, 8 bytes

　　OEM-specific Type

　　Header and Data:

　　D9 08 2A 00 01 02 00 00

　　Strings:

　　Handle 0x002B, DMI type 219, 11 bytes

　　OEM-specific Type

　　Header and Data:

　　DB 0B 2B 00 00 01 02 03 00 04 05

　　Strings:

　　Handle 0x002C, DMI type 220, 22 bytes

　　OEM-specific Type

　　Header and Data:

　　DC 16 2C 00 01 F0 00 00 02 F0 00 00 00 00 03 F0

　　04 F0 00 00 00 00

　　Handle 0x002D, DMI type 221, 19 bytes

　　OEM-specific Type

　　Header and Data:

　　DD 13 2D 00 00 00 00 00 00 03 00 00 00 00 00 00

　　00 00 00

　　Handle 0x002E, DMI type 222, 16 bytes

　　OEM-specific Type

　　Header and Data:

　　DE 10 2E 00 01 08 FF FF 00 00 00 00 00 00 00 00

　　Handle 0x0014, DMI type 16, 15 bytes

　　Physical Memory Array

　　Location: System Board Or Motherboard

　　Use: System Memory

　　Error Correction Type: None

　　Maximum Capacity: 16 GB

　　Error Information Handle: Not Provided

　　Number Of Devices: 2

　　Handle 0x0016, DMI type 20, 19 bytes

　　Memory Device Mapped Address

　　Starting Address: 0x00000000000

　　Ending Address: 0x000FFFFFFFF

　　Range Size: 4 GB

　　Physical Device Handle: 0x0015

　　Memory Array Mapped Address Handle: 0x0018

　　Partition Row Position: 1

　　Interleave Position: 1

　　Interleaved Data Depth: 1

　　Handle 0x0017, DMI type 17, 28 bytes

　　Memory Device

　　Array Handle: 0x0014

　　Error Information Handle: 0x0000

　　Total Width: Unknown

　　Data Width: Unknown

　　Size: No Module Installed

　　Form Factor: DIMM

　　Set: None

　　Locator: DIMM_B

　　Bank Locator: BANK 2

　　Type: Unknown

　　Type Detail: None

　　Speed: Unknown

　　Manufacturer: Not Specified

　　Serial Number: Not Specified

　　Asset Tag: Not Specified

　　Part Number: Not Specified

　　Rank: Unknown

　　Handle 0x0018, DMI type 19, 15 bytes

　　Memory Array Mapped Address

　　Starting Address: 0x00000000000

　　Ending Address: 0x000FFFFFFFF

　　Range Size: 4 GB

　　Physical Array Handle: 0x0014

　　Partition Width: 2

　　Handle 0x002F, DMI type 13, 22 bytes

　　BIOS Language Information

　　Language Description Format: Abbreviated

　　Installable Languages: 1

　　eng

　　Currently Installed Language: eng

　　Handle 0x0030, DMI type 131, 64 bytes

　　OEM-specific Type

　　Header and Data:

　　83 40 30 00 31 00 00 00 00 00 00 00 00 00 00 00

　　F8 00 4B 1C FF FF FF FF 01 00 00 00 00 00 07 00

　　AD 04 04 00 00 00 00 00 C8 00 FF FF 00 00 00 00

　　00 00 00 00 32 00 00 00 76 50 72 6F 00 00 00 00

　　Handle 0x0029, DMI type 216, 9 bytes

　　OEM-specific Type

　　Header and Data:

　　D8 09 29 00 01 02 01 00 00

　　Strings:

　　INTEL

　　0000

　　Handle 0x0000, DMI type 0, 24 bytes

　　BIOS Information

　　Vendor: Dell Inc.

　　Version: A05

　　Release Date: 08/03/2012

　　Address: 0xF0000

　　Runtime Size: 64 kB

　　ROM Size: 2048 kB

　　Characteristics:

　　MCA is supported

　　PCI is supported

　　BIOS is upgradeable

　　BIOS shadowing is allowed

　　ESCD support is available

　　Boot from CD is supported

　　Selectable boot is supported

　　BIOS ROM is socketed

　　EDD is supported

　　5.25"/1.2 MB floppy services are supported (int 13h)

　　3.5"/720 kB floppy services are supported (int 13h)

　　3.5"/2.88 MB floppy services are supported (int 13h)

　　Print screen service is supported (int 5h)

　　8042 keyboard services are supported (int 9h)

　　Serial services are supported (int 14h)

　　Printer services are supported (int 17h)

　　CGA/mono video services are supported (int 10h)

　　ACPI is supported

　　USB legacy is supported

　　ATAPI Zip drive boot is supported

　　BIOS boot specification is supported

　　Targeted content distribution is supported

　　BIOS Revision: 0.5

　　Firmware Revision: 0.5

　　Handle 0x0002, DMI type 2, 15 bytes

　　Base Board Information

　　Manufacturer: Dell Inc.

　　Product Name: 01HXXJ

　　Version: A05

　　Serial Number: .JSQ7PA1.CN7117623M00J2.

　　Asset Tag: Not Specified

　　Features:

　　Board is a hosting board

　　Board is replaceable

　　Location In Chassis: To Be Filled By O.E.M.

　　Chassis Handle: 0x0003

　　Type: Motherboard

　　Contained Object Handles: 0

　　Handle 0x0003, DMI type 3, 21 bytes

　　Chassis Information

　　Manufacturer: Dell Inc.

　　Type: Portable

　　Lock: Not Present

　　Version: Not Specified

　　Serial Number: JSR1

　　Asset Tag: Not Specified

　　Boot-up State: Safe

　　Power Supply State: Safe

　　Thermal State: Safe

　　Security Status: None

　　OEM Information: 0x00000000

　　Height: Unspecified

　　Number Of Power Cords: 1

　　Contained Elements: 0

　　Handle 0x0001, DMI type 1, 27 bytes

　　System Information

　　Manufacturer: Dell Inc.

　　Product Name: Inspiron N5050

　　Version: Not Specified

　　Serial Number: JSR1

　　UUID: 4C4C4544-0053-5110-8029-CAC05241

　　Wake-up Type: Power Switch

　　SKU Number: To be filled by O.E.M.

　　Family:

　　Handle 0x0024, DMI type 208, 12 bytes

　　OEM-specific Type

　　Header and Data:

　　D0 0C 24 00 02 05 FE 00 04 05 01 02

　　Strings:

　　20120323

　　20120323

　　Handle 0x0011, DMI type 10, 6 bytes

　　On Board Device Information

　　Type: Video

　　Status: Enabled

　　Description: Mobile Intel SandyBridge HD Graphics

　　Handle 0x0015, DMI type 17, 28 bytes

　　Memory Device

　　Array Handle: 0x0014

　　Error Information Handle: 0x0000

　　Total Width: 64 bits

　　Data Width: 64 bits

　　Size: 4096 MB

　　Form Factor: SODIMM

　　Set: None

　　Locator: DIMM_A

　　Bank Locator: BANK 0

　　Type: DDR3

　　Type Detail: Synchronous

　　Speed: 1067 MHz

　　Manufacturer: 014F

　　Serial Number: 0009F2

　　Asset Tag: 54114000

　　Part Number: JM1066-4G

　　Rank: Unknown

　　Handle 0x0031, DMI type 127, 4 bytes

　　End Of Table

　　結束。