首页 / 操作系统 / Linux / Linux系统入门教程：如何找出你的系统所支持的最大内存

大多数情况下你可以从BIOS、产品目录或者干脆手动找出你的系统所持的最大内存。这里，我们介绍一种简单有用的技巧——使用dmidecode来找出系统支持的最大内存，这样你就无需打开机箱或者参照BIOS和产品目录了。 

什么是 dmidecode？

就像你可能知道的一样， dmidecode是一个将计算机DMI（又名SMBIOS）表的内容转换为可读格式的工具。这个表包含了系统硬件组件的介绍以及其他一些如序列号和IOS版本等有用的信息。使用dmidecode你能够获取此项信息，而无需去探测真实的硬件。 

找出你的系统所支持的最大内存

请确定你已经在系统中安装了dmidecode，我觉得你的操作系统应该已经自动安装过了，不过并不非常确定。在基于Deb的系统中安装

1. sudo apt-get install dmidecode

在基于RPM的系统中安装

1. sudo yum install dmidecode

在SUSE/openSUSE中安装

1. sudo zypper in dmidecode

好了，我们已经安装了dmidecode，接下来让我们找出支持的最大内存。输入以下命令：

1. sudo dmidecode -t 16

输出样本

1. # dmidecode 2.12
2. SMBIOS 2.6 present.
3. Handle0x0014, DMI type 16,15 bytes
4. PhysicalMemoryArray
5. Location:SystemBoardOrMotherboard
6. Use:SystemMemory
7. ErrorCorrectionType:None
8. MaximumCapacity:16 GB
9. ErrorInformationHandle:NotProvided
10. NumberOfDevices:2

就像你看到的，我的系统支持最大内存到16G，并且有两个内存插槽，简单吧？接下来，让我们找出现在已经安装的内存的详细信息。

1. sudo dmidecode -t 17

输出样本

1. # dmidecode 2.12
2. SMBIOS 2.6 present.
3. Handle0x0017, DMI type 17,28 bytes
4. MemoryDevice
5. ArrayHandle:0x0014
6. ErrorInformationHandle:0x0000
7. TotalWidth:Unknown
8. DataWidth:Unknown
9. Size:NoModuleInstalled
10. FormFactor: DIMM
11. Set:None
12. Locator: DIMM_B
13. BankLocator: BANK 2
14. Type:Unknown
15. TypeDetail:None
16. Speed:Unknown
17. Manufacturer:NotSpecified
18. SerialNumber:NotSpecified
19. AssetTag:NotSpecified
20. PartNumber:NotSpecified
21. Rank:Unknown
22. Handle0x0015, DMI type 17,28 bytes
23. MemoryDevice
24. ArrayHandle:0x0014
25. ErrorInformationHandle:0x0000
26. TotalWidth:64 bits
27. DataWidth:64 bits
28. Size:4096 MB
29. FormFactor: SODIMM
30. Set:None
31. Locator: DIMM_A
32. BankLocator: BANK 0
33. Type: DDR3
34. TypeDetail:Synchronous
35. Speed:1067MHz
36. Manufacturer:014F
37. SerialNumber:00092AF2
38. AssetTag:54114000
39. PartNumber: JM1066KSN-4G
40. Rank:Unknown

就像上边输出的一样，我在插槽1里边安装了一个内存条。内存大小为4G，类型为DDR3，速度为1067 MHz。同样的，我们可以通过下边命令得到完整的内存信息。

1. sudo dmidecode -t memory
2. sudo dmidecode -t memory | less
3. sudo dmidecode -t memory | more

输出样本

1. # dmidecode 2.12
2. SMBIOS 2.6 present.
3. Handle0x0014, DMI type 16,15 bytes
4. PhysicalMemoryArray
5. Location:SystemBoardOrMotherboard
6. Use:SystemMemory
7. ErrorCorrectionType:None
8. MaximumCapacity:16 GB
9. ErrorInformationHandle:NotProvided
10. NumberOfDevices:2
11. Handle0x0017, DMI type 17,28 bytes
12. MemoryDevice
13. ArrayHandle:0x0014
14. ErrorInformationHandle:0x0000
15. TotalWidth:Unknown
16. DataWidth:Unknown
17. Size:NoModuleInstalled
18. FormFactor: DIMM
19. Set:None
20. Locator: DIMM_B
21. BankLocator: BANK 2
22. Type:Unknown
23. TypeDetail:None
24. Speed:Unknown
25. Manufacturer:NotSpecified
26. SerialNumber:NotSpecified
27. AssetTag:NotSpecified
28. PartNumber:NotSpecified
29. Rank:Unknown
30. Handle0x0015, DMI type 17,28 bytes
31. MemoryDevice
32. ArrayHandle:0x0014
33. ErrorInformationHandle:0x0000
34. TotalWidth:64 bits
35. DataWidth:64 bits
36. Size:4096 MB
37. FormFactor: SODIMM
38. Set:None
39. Locator: DIMM_A
40. BankLocator: BANK 0
41. Type: DDR3
42. TypeDetail:Synchronous
43. Speed:1067MHz
44. Manufacturer:014F
45. SerialNumber:00092AF2
46. AssetTag:54114000
47. PartNumber: JM1066KSN-4G
48. Rank:Unknown

如果你好奇想要知道整个系统的详细信息，例如主板、内存、BIOS等，那么可以输入以下命令来获取。sudo dmidecode输出样本

1. # dmidecode 2.12
2. SMBIOS 2.6 present.
3. 48 structures occupying 2173 bytes.
4. Table at 0x000EB840.
5. Handle0xDA00, DMI type 218,251 bytes
6. OEM-specific Type
7. HeaderandData:
8. DA FB 00 DA B2 000D5F0F37407D00000000
9. 007E0001000000 DC 0100800200 DD 0100
10. 8003007501018001007601028001002D
11. 01038001002E01038000008101078000
12. 00820107800100830108800000840108
13. 80010085010680000086010680010058
14. 02058000005702058001009C00020001
15. 009B00020000008A0103000100890103
16. 0000007F010400000080010400010053
17. 01050000005201050001007B01060000
18. 007C0106000100940107000000930107
19. 0001007D00080000002D00090001002E
20. 00090000006E000A00000095000B0001
21. 0096000B0000002F020C00010030020C
22. 00000050020D00000051020D00010052
23. 020D000200 FF FF 00000000
24. Handle0xDA01, DMI type 218,59 bytes
25. OEM-specific Type
26. HeaderandData:
27. DA 3B01 DA B2 000D5F0F374053020D0003
28. 0054020D00040056020D0005004B010E
29. 0001004A010E000000 EA 000F000100 EB
30. 000F000000 FF FF 00000000
31. Handle0x0004, DMI type 4,42 bytes
32. ProcessorInformation
33. SocketDesignation: CPU 1
34. Type:CentralProcessor
35. Family:Core i3
36. Manufacturer:Intel
37. ID: A7 060301 FF FB AB BE
38. Signature:Type0,Family6,Model42,Stepping7
39. Flags:
40. FPU （Floating-point unit on-chip）
41. VME （Virtual mode extension）
42. DE （Debugging extension）
43. PSE （Page size extension）
44. TSC （Time stamp counter）
45. MSR （Model specific registers）
46. PAE （Physical address extension）
47. MCE （Machine check exception）
48. CX8 （CMPXCHG8 instruction supported）
49. APIC （On-chip APIC hardware supported）
50. SEP （Fast system call）
51. MTRR （Memory type range registers）
52. PGE （Pageglobal enable）
53. MCA （Machine check architecture）
54. CMOV （Conditional move instruction supported）
55. PAT （Page attribute table）
56. PSE-36（36-bit page size extension）
57. CLFSH （CLFLUSH instruction supported）
58. DS （Debug store）
59. ACPI （ACPI supported）
60. MMX （MMX technology supported）
61. FXSR （FXSAVE and FXSTOR instructions supported）
62. SSE （Streaming SIMD extensions）
63. SSE2 （Streaming SIMD extensions 2）
64. SS （Self-snoop）
65. HTT （Multi-threading）
66. TM （Thermal monitor supported）
67. PBE （Pendingbreak enabled）
68. Version:Intel（R）Core（TM） i3-2350M CPU @2.30GHz
69. Voltage:1.1 V
70. ExternalClock:100MHz
71. MaxSpeed:2300MHz
72. CurrentSpeed:2300MHz
73. Status:Populated,Enabled
74. Upgrade:Other
75. L1 CacheHandle:0x0005
76. L2 CacheHandle:0x0006
77. L3 CacheHandle:0x0007
78. SerialNumber:ToBeFilledBy O.E.M.
79. AssetTag:ToBeFilledBy O.E.M.
80. PartNumber:ToBeFilledBy O.E.M.
81. CoreCount:2
82. CoreEnabled:1
83. ThreadCount:2
84. Characteristics:
85. 64-bit capable
86. Handle0x0005, DMI type 7,19 bytes
87. CacheInformation
88. SocketDesignation: L1-Cache
89. Configuration:Enabled,NotSocketed,Level1
90. OperationalMode:WriteBack
91. Location:Internal
92. InstalledSize:64 kB
93. MaximumSize:64 kB
94. Supported SRAM Types:
95. Other
96. Installed SRAM Type:Other
97. Speed:Unknown
98. ErrorCorrectionType:None
99. SystemType:Unified
100. Associativity:8-way Set-associative
101. Handle0x0006, DMI type 7,19 bytes
102. CacheInformation
103. SocketDesignation: L2-Cache
104. Configuration:Enabled,NotSocketed,Level2
105. OperationalMode:VariesWithMemoryAddress
106. Location:Internal
107. InstalledSize:512 kB
108. MaximumSize:512 kB
109. Supported SRAM Types:
110. Other
111. Installed SRAM Type:Other
112. Speed:Unknown
113. ErrorCorrectionType:None
114. SystemType:Unified
115. Associativity:8-way Set-associative
116. Handle0x0007, DMI type 7,19 bytes
117. CacheInformation
118. SocketDesignation: L3-Cache
119. Configuration:Enabled,NotSocketed,Level3
120. OperationalMode:VariesWithMemoryAddress
121. Location:Internal
122. InstalledSize:3072 kB
123. MaximumSize:3072 kB
124. Supported SRAM Types:
125. Other
126. Installed SRAM Type:Other
127. Speed:Unknown
128. ErrorCorrectionType:None
129. SystemType:Unified
130. Associativity:Other
131. Handle0x0008, DMI type 8,9 bytes
132. PortConnectorInformation
133. InternalReferenceDesignator: J1A1
134. InternalConnectorType:None
135. ExternalReferenceDesignator: PS2Mouse
136. ExternalConnectorType: PS/2
137. PortType:MousePort
138. Handle0x0009, DMI type 8,9 bytes
139. PortConnectorInformation
140. InternalReferenceDesignator: J1A1
141. InternalConnectorType:None
142. ExternalReferenceDesignator:Keyboard
143. ExternalConnectorType: PS/2
144. PortType:KeyboardPort
145. Handle0x000A, DMI type 8,9 bytes
146. PortConnectorInformation
147. InternalReferenceDesignator: J2A2B
148. InternalConnectorType:None
149. ExternalReferenceDesignator:Video
150. ExternalConnectorType: DB-15 female
151. PortType:VideoPort
152. Handle0x000B, DMI type 8,9 bytes
153. PortConnectorInformation
154. InternalReferenceDesignator: J3A1
155. InternalConnectorType:None
156. ExternalReferenceDesignator: USB1
157. ExternalConnectorType:AccessBus（USB）
158. PortType: USB
159. Handle0x000C, DMI type 8,9 bytes
160. PortConnectorInformation
161. InternalReferenceDesignator: J3A1
162. InternalConnectorType:None
163. ExternalReferenceDesignator: USB2
164. ExternalConnectorType:AccessBus（USB）
165. PortType: USB
166. Handle0x000D, DMI type 8,9 bytes
167. PortConnectorInformation
168. InternalReferenceDesignator: J3A1
169. InternalConnectorType:None
170. ExternalReferenceDesignator: USB3
171. ExternalConnectorType:AccessBus（USB）
172. PortType: USB
173. Handle0x000E, DMI type 8,9 bytes
174. PortConnectorInformation
175. InternalReferenceDesignator: J5A1
176. InternalConnectorType:None
177. ExternalReferenceDesignator: LAN
178. ExternalConnectorType: RJ-45
179. PortType:NetworkPort
180. Handle0x000F, DMI type 9,17 bytes
181. SystemSlotInformation
182. Designation: J6B2
183. Type: x16 PCI Express
184. CurrentUsage:InUse
185. Length:Long
186. ID:0
187. Characteristics:
188. 3.3 V is provided
189. Openingis shared
190. PME signal is supported
191. BusAddress:0000:00:01.0
192. Handle0x0010, DMI type 9,17 bytes
193. SystemSlotInformation
194. Designation: J6B1
195. Type: x1 PCI Express
196. CurrentUsage:InUse
197. Length:Short
198. ID:1
199. Characteristics:
200. 3.3 V is provided
201. Openingis shared
202. PME signal is supported
203. BusAddress:0000:00:1c.3
204. Handle0x0012, DMI type 11,5 bytes
205. OEM Strings
206. String1:DellSystem
207. String2:5[0003]
208. String3:13[P18F]
209. Handle0x0013, DMI type 12,5 bytes
210. SystemConfigurationOptions
211. Option1:ToBeFilledBy O.E.M.
212. Handle0x001C, DMI type 21,7 bytes
213. Built-inPointingDevice
214. Type:TouchPad
215. Interface:BusMouse
216. Buttons:2
217. Handle0x001D, DMI type 22,26 bytes
218. PortableBattery
219. Location:Sys.BatteryBay
220. Manufacturer:Sanyo
221. SerialNumber:5390
222. Name: DELL 4YRJH22
223. Chemistry:LithiumIon
224. DesignCapacity:45000 mWh
225. DesignVoltage:10800 mV
226. SBDS Version:1.0
227. MaximumError:2%
228. SBDS ManufactureDate:2012-02-28
229. OEM-specific Information:0x00000001
230. Handle0x001E, DMI type 32,20 bytes
231. SystemBootInformation
232. Status:No errors detected
233. Handle0x0020, DMI type 27,12 bytes
234. CoolingDevice
235. Type:Fan
236. Status: OK
237. OEM-specific Information:0x00000000
238. Handle0x0021, DMI type 28,20 bytes
239. TemperatureProbe
240. Description: CPU InternalTemperature
241. Location:Processor
242. Status: OK
243. MaximumValue:127.0 deg C
244. MinimumValue:0.0 deg C
245. Resolution:1.000 deg C
246. Tolerance:0.5 deg C
247. Accuracy:Unknown
248. OEM-specific Information:0x00000000
249. Handle0xB000, DMI type 176,5 bytes
250. OEM-specific Type
251. HeaderandData:
252. B0 0500 B0 00
253. Handle0xB100, DMI type 177,12 bytes
254. OEM-specific Type
255. HeaderandData:
256. B1 0C00 B1 1A0E000000000000
257. Handle0x0025, DMI type 209,12 bytes
258. OEM-specific Type
259. HeaderandData:
260. D1 0C25000000000305010003
261. Handle0x0026, DMI type 210,12 bytes
262. OEM-specific Type
263. HeaderandData:
264. D2 0C26000000000305200103
265. Handle0x0027, DMI type 211,13 bytes
266. OEM-specific Type
267. HeaderandData:
268. D3 0D2700010000000002030404
269. Strings:
270. Front
271. Handle0x0028, DMI type 212,57 bytes
272. OEM-specific Type
273. HeaderandData:
274. D4 39280070007100014950489C0049 FC
275. 019B0049 FC 007F014A FB 0480014A FB 00
276. 53014A F7 0852014A F7 087B014A EF 107C
277. 014A EF 10 FF FF 000000
278. Handle0x002A, DMI type 217,8 bytes
279. OEM-specific Type
280. HeaderandData:
281. D9 082A0001020000
282. Strings:
283. Handle0x002B, DMI type 219,11 bytes
284. OEM-specific Type
285. HeaderandData:
286. DB 0B2B0000010203000405
287. Strings:
288. Handle0x002C, DMI type 220,22 bytes
289. OEM-specific Type
290. HeaderandData:
291. DC 162C0001 F0 000002 F0 0000000003 F0
292. 04 F0 00000000
293. Handle0x002D, DMI type 221,19 bytes
294. OEM-specific Type
295. HeaderandData:
296. DD 132D00000000000003000000000000
297. 000000
298. Handle0x002E, DMI type 222,16 bytes
299. OEM-specific Type
300. HeaderandData:
301. DE 102E000108 FF FF 0000000000000000
302. Handle0x0014, DMI type 16,15 bytes
303. PhysicalMemoryArray
304. Location:SystemBoardOrMotherboard
305. Use:SystemMemory
306. ErrorCorrectionType:None
307. MaximumCapacity:16 GB
308. ErrorInformationHandle:NotProvided
309. NumberOfDevices:2
310. Handle0x0016, DMI type 20,19 bytes
311. MemoryDeviceMappedAddress
312. StartingAddress:0x00000000000
313. EndingAddress:0x000FFFFFFFF
314. RangeSize:4 GB
315. PhysicalDeviceHandle:0x0015
316. MemoryArrayMappedAddressHandle:0x0018
317. PartitionRowPosition:1
318. InterleavePosition:1
319. InterleavedDataDepth:1
320. Handle0x0017, DMI type 17,28 bytes
321. MemoryDevice
322. ArrayHandle:0x0014
323. ErrorInformationHandle:0x0000
324. TotalWidth:Unknown
325. DataWidth:Unknown
326. Size:NoModuleInstalled
327. FormFactor: DIMM
328. Set:None
329. Locator: DIMM_B
330. BankLocator: BANK 2
331. Type:Unknown
332. TypeDetail:None
333. Speed:Unknown
334. Manufacturer:NotSpecified
335. SerialNumber:NotSpecified
336. AssetTag:NotSpecified
337. PartNumber:NotSpecified
338. Rank:Unknown
339. Handle0x0018, DMI type 19,15 bytes
340. MemoryArrayMappedAddress
341. StartingAddress:0x00000000000
342. EndingAddress:0x000FFFFFFFF
343. RangeSize:4 GB
344. PhysicalArrayHandle:0x0014
345. PartitionWidth:2
346. Handle0x002F, DMI type 13,22 bytes
347. BIOS LanguageInformation
348. LanguageDescriptionFormat:Abbreviated
349. InstallableLanguages:1
350. eng
351. CurrentlyInstalledLanguage: eng
352. Handle0x0030, DMI type 131,64 bytes
353. OEM-specific Type
354. HeaderandData:
355. 83403000310000000000000000000000
356. F8 004B1C FF FF FF FF 0100000000000700
357. AD 04040000000000 C8 00 FF FF 00000000
358. 00000000320000007650726F00000000
359. Handle0x0029, DMI type 216,9 bytes
360. OEM-specific Type
361. HeaderandData:
362. D8 0929000102010000
363. Strings:
364. INTEL
365. 0000
366. Handle0x0000, DMI type 0,24 bytes
367. BIOS Information
368. Vendor:DellInc.
369. Version: A05
370. ReleaseDate:08/03/2012
371. Address:0xF0000
372. RuntimeSize:64 kB
373. ROM Size:2048 kB
374. Characteristics:
375. MCA is supported
376. PCI is supported
377. BIOS is upgradeable
378. BIOS shadowing is allowed
379. ESCD support is available
380. Bootfrom CD is supported
381. Selectable boot is supported
382. BIOS ROM is socketed
383. EDD is supported
384. 5.25"/1.2 MB floppy services are supported （int 13h）
385. 3.5"/720 kB floppy services are supported （int13h）
386. 3.5"/2.88 MB floppy services are supported （int 13h）
387. Print screen service is supported （int 5h）
388. 8042 keyboard services are supported （int 9h）
389. Serial services are supported （int 14h）
390. Printer services are supported （int 17h）
391. CGA/mono video services are supported （int 10h）
392. ACPI is supported
393. USB legacy is supported
394. ATAPI Zip drive boot is supported
395. BIOS boot specification is supported
396. Targeted content distribution is supported
397. BIOS Revision: 0.5
398. Firmware Revision: 0.5
399. Handle 0x0002, DMI type 2, 15 bytes
400. Base Board Information
401. Manufacturer: Dell Inc.
402. Product Name: 01HXXJ
403. Version: A05
404. Serial Number: .JSQ7PA1.CN7117623M00J2.
405. Asset Tag: Not Specified
406. Features:
407. Board is a hosting board
408. Board is replaceable
409. Location In Chassis: To Be Filled By O.E.M.
410. Chassis Handle: 0x0003
411. Type: Motherboard
412. Contained Object Handles: 0
413. Handle 0x0003, DMI type 3, 21 bytes
414. Chassis Information
415. Manufacturer: Dell Inc.
416. Type: Portable
417. Lock: Not Present
418. Version: Not Specified
419. Serial Number: JSR1
420. Asset Tag: Not Specified
421. Boot-up State: Safe
422. Power Supply State: Safe
423. Thermal State: Safe
424. Security Status: None
425. OEM Information: 0x00000000
426. Height: Unspecified
427. Number Of Power Cords: 1
428. Contained Elements: 0
429. Handle 0x0001, DMI type 1, 27 bytes
430. System Information
431. Manufacturer: Dell Inc.
432. Product Name: Inspiron N5050
433. Version: Not Specified
434. Serial Number: JSR1
435. UUID: 4C4C4544-0053-5110-8029-CAC05241
436. Wake-up Type: Power Switch
437. SKU Number: To be filled by O.E.M.
438. Family:
439. Handle 0x0024, DMI type 208, 12 bytes
440. OEM-specific Type
441. Header and Data:
442. D0 0C 24 00 02 05 FE 00 04 05 01 02
443. Strings:
444. 20120323
445. 20120323
446. Handle 0x0011, DMI type 10, 6 bytes
447. On Board Device Information
448. Type: Video
449. Status: Enabled
450. Description: Mobile Intel SandyBridge HD Graphics
451. Handle 0x0015, DMI type 17, 28 bytes
452. Memory Device
453. Array Handle: 0x0014
454. Error Information Handle: 0x0000
455. Total Width: 64 bits
456. Data Width: 64 bits
457. Size: 4096 MB
458. Form Factor: SODIMM
459. Set: None
460. Locator: DIMM_A
461. Bank Locator: BANK 0
462. Type: DDR3
463. Type Detail: Synchronous
464. Speed: 1067 MHz
465. Manufacturer: 014F
466. Serial Number: 0009F2
467. Asset Tag: 54114000
468. Part Number: JM1066-4G
469. Rank: Unknown
470. Handle 0x0031, DMI type 127, 4 bytes
471. End Of Table

好了，就是这样。本文永久更新链接地址