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.
4. Handle 0x0014, DMI type 16, 15 bytes
5. Physical Memory Array
6. Location: System Board Or Motherboard
7. Use: System Memory
8. Error Correction Type: None
9. Maximum Capacity: 16 GB
10. Error Information Handle: Not Provided
11. Number Of Devices: 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.
4. Handle 0x0017, DMI type 17, 28 bytes
5. Memory Device
6. Array Handle: 0x0014
7. Error Information Handle: 0x0000
8. Total Width: Unknown
9. Data Width: Unknown
10. Size: No Module Installed
11. Form Factor: DIMM
12. Set: None
13. Locator: DIMM_B
14. Bank Locator: BANK 2
15. Type: Unknown
16. Type Detail: None
17. Speed: Unknown
18. Manufacturer: Not Specified
19. Serial Number: Not Specified
20. Asset Tag: Not Specified
21. Part Number: Not Specified
22. Rank: Unknown
24. Handle 0x0015, DMI type 17, 28 bytes
25. Memory Device
26. Array Handle: 0x0014
27. Error Information Handle: 0x0000
28. Total Width: 64 bits
29. Data Width: 64 bits
30. Size: 4096 MB
31. Form Factor: SODIMM
32. Set: None
33. Locator: DIMM_A
34. Bank Locator: BANK 0
35. Type: DDR3
36. Type Detail: Synchronous
37. Speed: 1067 MHz
38. Manufacturer: 014F
39. Serial Number: 00092AF2
40. Asset Tag: 54114000
41. Part Number: JM1066KSN-4G
42. 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.
4. Handle 0x0014, DMI type 16, 15 bytes
5. Physical Memory Array
6. Location: System Board Or Motherboard
7. Use: System Memory
8. Error Correction Type: None
9. Maximum Capacity: 16 GB
10. Error Information Handle: Not Provided
11. Number Of Devices: 2
13. Handle 0x0017, DMI type 17, 28 bytes
14. Memory Device
15. Array Handle: 0x0014
16. Error Information Handle: 0x0000
17. Total Width: Unknown
18. Data Width: Unknown
19. Size: No Module Installed
20. Form Factor: DIMM
21. Set: None
22. Locator: DIMM_B
23. Bank Locator: BANK 2
24. Type: Unknown
25. Type Detail: None
26. Speed: Unknown
27. Manufacturer: Not Specified
28. Serial Number: Not Specified
29. Asset Tag: Not Specified
30. Part Number: Not Specified
31. Rank: Unknown
33. Handle 0x0015, DMI type 17, 28 bytes
34. Memory Device
35. Array Handle: 0x0014
36. Error Information Handle: 0x0000
37. Total Width: 64 bits
38. Data Width: 64 bits
39. Size: 4096 MB
40. Form Factor: SODIMM
41. Set: None
42. Locator: DIMM_A
43. Bank Locator: BANK 0
44. Type: DDR3
45. Type Detail: Synchronous
46. Speed: 1067 MHz
47. Manufacturer: 014F
48. Serial Number: 00092AF2
49. Asset Tag: 54114000
50. Part Number: JM1066KSN-4G
51. 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.
6. Handle 0xDA00, DMI type 218, 251 bytes
7. OEM-specific Type
8. Header and Data:
9. DA FB 00 DA B2 00 0D 5F 0F 37 40 7D 00 00 00 00
10. 00 7E 00 01 00 00 00 DC 01 00 80 02 00 DD 01 00
11. 80 03 00 75 01 01 80 01 00 76 01 02 80 01 00 2D
12. 01 03 80 01 00 2E 01 03 80 00 00 81 01 07 80 00
13. 00 82 01 07 80 01 00 83 01 08 80 00 00 84 01 08
14. 80 01 00 85 01 06 80 00 00 86 01 06 80 01 00 58
15. 02 05 80 00 00 57 02 05 80 01 00 9C 00 02 00 01
16. 00 9B 00 02 00 00 00 8A 01 03 00 01 00 89 01 03
17. 00 00 00 7F 01 04 00 00 00 80 01 04 00 01 00 53
18. 01 05 00 00 00 52 01 05 00 01 00 7B 01 06 00 00
19. 00 7C 01 06 00 01 00 94 01 07 00 00 00 93 01 07
20. 00 01 00 7D 00 08 00 00 00 2D 00 09 00 01 00 2E
21. 00 09 00 00 00 6E 00 0A 00 00 00 95 00 0B 00 01
22. 00 96 00 0B 00 00 00 2F 02 0C 00 01 00 30 02 0C
23. 00 00 00 50 02 0D 00 00 00 51 02 0D 00 01 00 52
24. 02 0D 00 02 00 FF FF 00 00 00 00
26. Handle 0xDA01, DMI type 218, 59 bytes
27. OEM-specific Type
28. Header and Data:
29. DA 3B 01 DA B2 00 0D 5F 0F 37 40 53 02 0D 00 03
30. 00 54 02 0D 00 04 00 56 02 0D 00 05 00 4B 01 0E
31. 00 01 00 4A 01 0E 00 00 00 EA 00 0F 00 01 00 EB
32. 00 0F 00 00 00 FF FF 00 00 00 00
34. Handle 0x0004, DMI type 4, 42 bytes
35. Processor Information
36. Socket Designation: CPU 1
37. Type: Central Processor
38. Family: Core i3
39. Manufacturer: Intel
40. ID: A7 06 03 01 FF FB AB BE
41. Signature: Type 0, Family 6, Model 42, Stepping 7
42. Flags:
43. FPU (Floating-point unit on-chip)
44. VME (Virtual mode extension)
45. DE (Debugging extension)
46. PSE (Page size extension)
47. TSC (Time stamp counter)
48. MSR (Model specific registers)
49. PAE (Physical address extension)
50. MCE (Machine check exception)
51. CX8 (CMPXCHG8 instruction supported)
52. APIC (On-chip APIC hardware supported)
53. SEP (Fast system call)
54. MTRR (Memory type range registers)
55. PGE (Page global enable)
56. MCA (Machine check architecture)
57. CMOV (Conditional move instruction supported)
58. PAT (Page attribute table)
59. PSE-36 (36-bit page size extension)
60. CLFSH (CLFLUSH instruction supported)
61. DS (Debug store)
62. ACPI (ACPI supported)
63. MMX (MMX technology supported)
64. FXSR (FXSAVE and FXSTOR instructions supported)
65. SSE (Streaming SIMD extensions)
66. SSE2 (Streaming SIMD extensions 2)
67. SS (Self-snoop)
68. HTT (Multi-threading)
69. TM (Thermal monitor supported)
70. PBE (Pending break enabled)
71. Version: Intel(R) Core(TM) i3-2350M CPU @ 2.30GHz
72. Voltage: 1.1 V
73. External Clock: 100 MHz
74. Max Speed: 2300 MHz
75. Current Speed: 2300 MHz
76. Status: Populated, Enabled
77. Upgrade: Other
78. L1 Cache Handle: 0x0005
79. L2 Cache Handle: 0x0006
80. L3 Cache Handle: 0x0007
81. Serial Number: To Be Filled By O.E.M.
82. Asset Tag: To Be Filled By O.E.M.
83. Part Number: To Be Filled By O.E.M.
84. Core Count: 2
85. Core Enabled: 1
86. Thread Count: 2
87. Characteristics:
88. 64-bit capable
90. Handle 0x0005, DMI type 7, 19 bytes
91. Cache Information
92. Socket Designation: L1-Cache
93. Configuration: Enabled, Not Socketed, Level 1
94. Operational Mode: Write Back
95. Location: Internal
96. Installed Size: 64 kB
97. Maximum Size: 64 kB
98. Supported SRAM Types:
99. Other
100. Installed SRAM Type: Other
101. Speed: Unknown
102. Error Correction Type: None
103. System Type: Unified
104. Associativity: 8-way Set-associative
106. Handle 0x0006, DMI type 7, 19 bytes
107. Cache Information
108. Socket Designation: L2-Cache
109. Configuration: Enabled, Not Socketed, Level 2
110. Operational Mode: Varies With Memory Address
111. Location: Internal
112. Installed Size: 512 kB
113. Maximum Size: 512 kB
114. Supported SRAM Types:
115. Other
116. Installed SRAM Type: Other
117. Speed: Unknown
118. Error Correction Type: None
119. System Type: Unified
120. Associativity: 8-way Set-associative
122. Handle 0x0007, DMI type 7, 19 bytes
123. Cache Information
124. Socket Designation: L3-Cache
125. Configuration: Enabled, Not Socketed, Level 3
126. Operational Mode: Varies With Memory Address
127. Location: Internal
128. Installed Size: 3072 kB
129. Maximum Size: 3072 kB
130. Supported SRAM Types:
131. Other
132. Installed SRAM Type: Other
133. Speed: Unknown
134. Error Correction Type: None
135. System Type: Unified
136. Associativity: Other
138. Handle 0x0008, DMI type 8, 9 bytes
139. Port Connector Information
140. Internal Reference Designator: J1A1
141. Internal Connector Type: None
142. External Reference Designator: PS2Mouse
143. External Connector Type: PS/2
144. Port Type: Mouse Port
146. Handle 0x0009, DMI type 8, 9 bytes
147. Port Connector Information
148. Internal Reference Designator: J1A1
149. Internal Connector Type: None
150. External Reference Designator: Keyboard
151. External Connector Type: PS/2
152. Port Type: Keyboard Port
154. Handle 0x000A, DMI type 8, 9 bytes
155. Port Connector Information
156. Internal Reference Designator: J2A2B
157. Internal Connector Type: None
158. External Reference Designator: Video
159. External Connector Type: DB-15 female
160. Port Type: Video Port
162. Handle 0x000B, DMI type 8, 9 bytes
163. Port Connector Information
164. Internal Reference Designator: J3A1
165. Internal Connector Type: None
166. External Reference Designator: USB1
167. External Connector Type: Access Bus (USB)
168. Port Type: USB
170. Handle 0x000C, DMI type 8, 9 bytes
171. Port Connector Information
172. Internal Reference Designator: J3A1
173. Internal Connector Type: None
174. External Reference Designator: USB2
175. External Connector Type: Access Bus (USB)
176. Port Type: USB
178. Handle 0x000D, DMI type 8, 9 bytes
179. Port Connector Information
180. Internal Reference Designator: J3A1
181. Internal Connector Type: None
182. External Reference Designator: USB3
183. External Connector Type: Access Bus (USB)
184. Port Type: USB
186. Handle 0x000E, DMI type 8, 9 bytes
187. Port Connector Information
188. Internal Reference Designator: J5A1
189. Internal Connector Type: None
190. External Reference Designator: LAN
191. External Connector Type: RJ-45
192. Port Type: Network Port
194. Handle 0x000F, DMI type 9, 17 bytes
195. System Slot Information
196. Designation: J6B2
197. Type: x16 PCI Express
198. Current Usage: In Use
199. Length: Long
200. ID: 0
201. Characteristics:
202. 3.3 V is provided
203. Opening is shared
204. PME signal is supported
205. Bus Address: 0000:00:01.0
207. Handle 0x0010, DMI type 9, 17 bytes
208. System Slot Information
209. Designation: J6B1
210. Type: x1 PCI Express
211. Current Usage: In Use
212. Length: Short
213. ID: 1
214. Characteristics:
215. 3.3 V is provided
216. Opening is shared
217. PME signal is supported
218. Bus Address: 0000:00:1c.3
220. Handle 0x0012, DMI type 11, 5 bytes
221. OEM Strings
222. String 1: Dell System
223. String 2: 5[0003]
224. String 3: 13[P18F]
226. Handle 0x0013, DMI type 12, 5 bytes
227. System Configuration Options
228. Option 1: To Be Filled By O.E.M.
230. Handle 0x001C, DMI type 21, 7 bytes
231. Built-in Pointing Device
232. Type: Touch Pad
233. Interface: Bus Mouse
234. Buttons: 2
236. Handle 0x001D, DMI type 22, 26 bytes
237. Portable Battery
238. Location: Sys. Battery Bay
239. Manufacturer: Sanyo
240. Serial Number: 5390
241. Name: DELL 4YRJH22
242. Chemistry: Lithium Ion
243. Design Capacity: 45000 mWh
244. Design Voltage: 10800 mV
245. SBDS Version: 1.0
246. Maximum Error: 2%
247. SBDS Manufacture Date: 2012-02-28
248. OEM-specific Information: 0x00000001
250. Handle 0x001E, DMI type 32, 20 bytes
251. System Boot Information
252. Status: No errors detected
254. Handle 0x0020, DMI type 27, 12 bytes
255. Cooling Device
256. Type: Fan
257. Status: OK
258. OEM-specific Information: 0x00000000
260. Handle 0x0021, DMI type 28, 20 bytes
261. Temperature Probe
262. Description: CPU Internal Temperature
263. Location: Processor
264. Status: OK
265. Maximum Value: 127.0 deg C
266. Minimum Value: 0.0 deg C
267. Resolution: 1.000 deg C
268. Tolerance: 0.5 deg C
269. Accuracy: Unknown
270. OEM-specific Information: 0x00000000
272. Handle 0xB000, DMI type 176, 5 bytes
273. OEM-specific Type
274. Header and Data:
275. B0 05 00 B0 00
277. Handle 0xB100, DMI type 177, 12 bytes
278. OEM-specific Type
279. Header and Data:
280. B1 0C 00 B1 1A 0E 00 00 00 00 00 00
282. Handle 0x0025, DMI type 209, 12 bytes
283. OEM-specific Type
284. Header and Data:
285. D1 0C 25 00 00 00 00 03 05 01 00 03
287. Handle 0x0026, DMI type 210, 12 bytes
288. OEM-specific Type
289. Header and Data:
290. D2 0C 26 00 00 00 00 03 05 20 01 03
292. Handle 0x0027, DMI type 211, 13 bytes
293. OEM-specific Type
294. Header and Data:
295. D3 0D 27 00 01 00 00 00 00 02 03 04 04
296. Strings:
297. Front
299. Handle 0x0028, DMI type 212, 57 bytes
300. OEM-specific Type
301. Header and Data:
302. D4 39 28 00 70 00 71 00 01 49 50 48 9C 00 49 FC
303. 01 9B 00 49 FC 00 7F 01 4A FB 04 80 01 4A FB 00
304. 53 01 4A F7 08 52 01 4A F7 08 7B 01 4A EF 10 7C
305. 01 4A EF 10 FF FF 00 00 00
307. Handle 0x002A, DMI type 217, 8 bytes
308. OEM-specific Type
309. Header and Data:
310. D9 08 2A 00 01 02 00 00
311. Strings:
313. Handle 0x002B, DMI type 219, 11 bytes
314. OEM-specific Type
315. Header and Data:
316. DB 0B 2B 00 00 01 02 03 00 04 05
317. Strings:
319. Handle 0x002C, DMI type 220, 22 bytes
320. OEM-specific Type
321. Header and Data:
322. DC 16 2C 00 01 F0 00 00 02 F0 00 00 00 00 03 F0
323. 04 F0 00 00 00 00
325. Handle 0x002D, DMI type 221, 19 bytes
326. OEM-specific Type
327. Header and Data:
328. DD 13 2D 00 00 00 00 00 00 03 00 00 00 00 00 00
329. 00 00 00
331. Handle 0x002E, DMI type 222, 16 bytes
332. OEM-specific Type
333. Header and Data:
334. DE 10 2E 00 01 08 FF FF 00 00 00 00 00 00 00 00
336. Handle 0x0014, DMI type 16, 15 bytes
337. Physical Memory Array
338. Location: System Board Or Motherboard
339. Use: System Memory
340. Error Correction Type: None
341. Maximum Capacity: 16 GB
342. Error Information Handle: Not Provided
343. Number Of Devices: 2
345. Handle 0x0016, DMI type 20, 19 bytes
346. Memory Device Mapped Address
347. Starting Address: 0x00000000000
348. Ending Address: 0x000FFFFFFFF
349. Range Size: 4 GB
350. Physical Device Handle: 0x0015
351. Memory Array Mapped Address Handle: 0x0018
352. Partition Row Position: 1
353. Interleave Position: 1
354. Interleaved Data Depth: 1
356. Handle 0x0017, DMI type 17, 28 bytes
357. Memory Device
358. Array Handle: 0x0014
359. Error Information Handle: 0x0000
360. Total Width: Unknown
361. Data Width: Unknown
362. Size: No Module Installed
363. Form Factor: DIMM
364. Set: None
365. Locator: DIMM_B
366. Bank Locator: BANK 2
367. Type: Unknown
368. Type Detail: None
369. Speed: Unknown
370. Manufacturer: Not Specified
371. Serial Number: Not Specified
372. Asset Tag: Not Specified
373. Part Number: Not Specified
374. Rank: Unknown
376. Handle 0x0018, DMI type 19, 15 bytes
377. Memory Array Mapped Address
378. Starting Address: 0x00000000000
379. Ending Address: 0x000FFFFFFFF
380. Range Size: 4 GB
381. Physical Array Handle: 0x0014
382. Partition Width: 2
384. Handle 0x002F, DMI type 13, 22 bytes
385. BIOS Language Information
386. Language Description Format: Abbreviated
387. Installable Languages: 1
388. eng
389. Currently Installed Language: eng
391. Handle 0x0030, DMI type 131, 64 bytes
392. OEM-specific Type
393. Header and Data:
394. 83 40 30 00 31 00 00 00 00 00 00 00 00 00 00 00
395. F8 00 4B 1C FF FF FF FF 01 00 00 00 00 00 07 00
396. AD 04 04 00 00 00 00 00 C8 00 FF FF 00 00 00 00
397. 00 00 00 00 32 00 00 00 76 50 72 6F 00 00 00 00
399. Handle 0x0029, DMI type 216, 9 bytes
400. OEM-specific Type
401. Header and Data:
402. D8 09 29 00 01 02 01 00 00
403. Strings:
404. INTEL
405. 0000
407. Handle 0x0000, DMI type 0, 24 bytes
408. BIOS Information
409. Vendor: Dell Inc.
410. Version: A05
411. Release Date: 08/03/2012
412. Address: 0xF0000
413. Runtime Size: 64 kB
414. ROM Size: 2048 kB
415. Characteristics:
416. MCA is supported
417. PCI is supported
418. BIOS is upgradeable
419. BIOS shadowing is allowed
420. ESCD support is available
421. Boot from CD is supported
422. Selectable boot is supported
423. BIOS ROM is socketed
424. EDD is supported
425. 5.25"/1.2 MB floppy services are supported (int 13h)
426. 3.5"/720 kB floppy services are supported (int 13h)
427. 3.5"/2.88 MB floppy services are supported (int 13h)
428. Print screen service is supported (int 5h)
429. 8042 keyboard services are supported (int 9h)
430. Serial services are supported (int 14h)
431. Printer services are supported (int 17h)
432. CGA/mono video services are supported (int 10h)
433. ACPI is supported
434. USB legacy is supported
435. ATAPI Zip drive boot is supported
436. BIOS boot specification is supported
437. Targeted content distribution is supported
438. BIOS Revision: 0.5
439. Firmware Revision: 0.5
441. Handle 0x0002, DMI type 2, 15 bytes
442. Base Board Information
443. Manufacturer: Dell Inc.
444. Product Name: 01HXXJ
445. Version: A05
446. Serial Number: .JSQ7PA1.CN7117623M00J2.
447. Asset Tag: Not Specified
448. Features:
449. Board is a hosting board
450. Board is replaceable
451. Location In Chassis: To Be Filled By O.E.M.
452. Chassis Handle: 0x0003
453. Type: Motherboard
454. Contained Object Handles: 0
456. Handle 0x0003, DMI type 3, 21 bytes
457. Chassis Information
458. Manufacturer: Dell Inc.
459. Type: Portable
460. Lock: Not Present
461. Version: Not Specified
462. Serial Number: JSR1
463. Asset Tag: Not Specified
464. Boot-up State: Safe
465. Power Supply State: Safe
466. Thermal State: Safe
467. Security Status: None
468. OEM Information: 0x00000000
469. Height: Unspecified
470. Number Of Power Cords: 1
471. Contained Elements: 0
473. Handle 0x0001, DMI type 1, 27 bytes
474. System Information
475. Manufacturer: Dell Inc.
476. Product Name: Inspiron N5050
477. Version: Not Specified
478. Serial Number: JSR1
479. UUID: 4C4C4544-0053-5110-8029-CAC05241
480. Wake-up Type: Power Switch
481. SKU Number: To be filled by O.E.M.
482. Family:
484. Handle 0x0024, DMI type 208, 12 bytes
485. OEM-specific Type
486. Header and Data:
487. D0 0C 24 00 02 05 FE 00 04 05 01 02
488. Strings:
489. 20120323
490. 20120323
492. Handle 0x0011, DMI type 10, 6 bytes
493. On Board Device Information
494. Type: Video
495. Status: Enabled
496. Description: Mobile Intel SandyBridge HD Graphics
498. Handle 0x0015, DMI type 17, 28 bytes
499. Memory Device
500. Array Handle: 0x0014
501. Error Information Handle: 0x0000
502. Total Width: 64 bits
503. Data Width: 64 bits
504. Size: 4096 MB
505. Form Factor: SODIMM
506. Set: None
507. Locator: DIMM_A
508. Bank Locator: BANK 0
509. Type: DDR3
510. Type Detail: Synchronous
511. Speed: 1067 MHz
512. Manufacturer: 014F
513. Serial Number: 0009F2
514. Asset Tag: 54114000
515. Part Number: JM1066-4G
516. Rank: Unknown
518. Handle 0x0031, DMI type 127, 4 bytes
519. End Of Table

好了，就是这样。

原文发布时间：2015-03-31

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