HDDについてメモ。
コンピュータシステムで最重要パーツは何だろうと考えてみた。
それってHDDかな。
HDDというか「その中に保存されているデータ」が重要だ。
ただ、そんな大切なものをしまっている場所なのに、
動作中HDDは常に秒速3,000～10,000回転という「超スピード」で
円盤を回転させ続けている。
しかも、回転によって発生する気流を利用して
数μの高さにヘッドを浮かして動作している恐るべき装置だ。
ディスク情報の表示には「hdparm」を使う。
ディスクの設定変更も出来るツールなので慎重に扱おう。
ディスクのモデルやシリアル情報、回転数なんかも確認できる。
■ディスク情報の表示（サマリ）
# hdparm -i /dev/sda
/dev/sda:
Model=Hitachi HTS725050A9A364, FwRev=PC4OC70E, SerialNo=************************
Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs }
RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=4
BuffType=DualPortCache, BuffSize=15151kB, MaxMultSect=16, MultSect=16
CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=976773168
IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
PIO modes: pio0 pio1 pio2 pio3 pio4
DMA modes: mdma0 mdma1 mdma2
UDMA modes: udma0 udma1 udma2 udma3 udma4 udma5 *udma6
AdvancedPM=yes: mode=0x80 (128) WriteCache=enabled
Drive conforms to: unknown: ATA/ATAPI-2,3,4,5,6,7
* signifies the current active mode
/dev/sda:
Model=Hitachi HTS725050A9A364, FwRev=PC4OC70E, SerialNo=************************
Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs }
RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=4
BuffType=DualPortCache, BuffSize=15151kB, MaxMultSect=16, MultSect=16
CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=976773168
IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
PIO modes: pio0 pio1 pio2 pio3 pio4
DMA modes: mdma0 mdma1 mdma2
UDMA modes: udma0 udma1 udma2 udma3 udma4 udma5 *udma6
AdvancedPM=yes: mode=0x80 (128) WriteCache=enabled
Drive conforms to: unknown: ATA/ATAPI-2,3,4,5,6,7
* signifies the current active mode
■ディスク情報の表示（詳細）
# hdparm -I /dev/sda
/dev/sda:
ATA device, with non-removable media
Model Number: Hitachi HTS725050A9A364
Serial Number: *****************
Firmware Revision: PC4OC70E
Transport: Serial, ATA8-AST, SATA 1.0a, SATA II Extensions, SATA Rev 2.5, SATA Rev 2.6; Revision: ATA8-AST T13 Project D1697 Revision 0b
Standards:
Used: unknown (minor revision code 0x0028)
Supported: 8 7 6 5
Likely used: 8
Configuration:
Logical max current
cylinders 16383 16383
heads 16 16
sectors/track 63 63
--
CHS current addressable sectors: 16514064
LBA user addressable sectors: 268435455
LBA48 user addressable sectors: 976773168
Logical/Physical Sector size: 512 bytes
device size with M = 1024*1024: 476940 MBytes
device size with M = 1000*1000: 500107 MBytes (500 GB)
cache/buffer size = 15151 KBytes (type=DualPortCache)
Form Factor: 2.5 inch
Nominal Media Rotation Rate: 7200
Capabilities:
LBA, IORDY(can be disabled)
Queue depth: 32
Standby timer values: spec'd by Vendor, no device specific minimum
R/W multiple sector transfer: Max = 16 Current = 16
Advanced power management level: 128
Recommended acoustic management value: 128, current value: 254
DMA: mdma0 mdma1 mdma2 udma0 udma1 udma2 udma3 udma4 udma5 *udma6
Cycle time: min=120ns recommended=120ns
PIO: pio0 pio1 pio2 pio3 pio4
Cycle time: no flow control=120ns IORDY flow control=120ns
Commands/features:
Enabled Supported:
* SMART feature set
Security Mode feature set
* Power Management feature set
* Write cache
* Look-ahead
* Host Protected Area feature set
* WRITE_BUFFER command
* READ_BUFFER command
* NOP cmd
* DOWNLOAD_MICROCODE
* Advanced Power Management feature set
Power-Up In Standby feature set
* SET_FEATURES required to spinup after power up
SET_MAX security extension
Automatic Acoustic Management feature set
* 48-bit Address feature set
* Device Configuration Overlay feature set
* Mandatory FLUSH_CACHE
* FLUSH_CACHE_EXT
* SMART error logging
* SMART self-test
* General Purpose Logging feature set
* WRITE_{DMA|MULTIPLE}_FUA_EXT
* 64-bit World wide name
* IDLE_IMMEDIATE with UNLOAD
* WRITE_UNCORRECTABLE_EXT command
* {READ,WRITE}_DMA_EXT_GPL commands
* Segmented DOWNLOAD_MICROCODE
* Gen1 signaling speed (1.5Gb/s)
* Gen2 signaling speed (3.0Gb/s)
* Native Command Queueing (NCQ)
* Host-initiated interface power management
* Phy event counters
* NCQ priority information
Non-Zero buffer offsets in DMA Setup FIS
DMA Setup Auto-Activate optimization
Device-initiated interface power management
In-order data delivery
* Software settings preservation
* SMART Command Transport (SCT) feature set
* SCT LBA Segment Access (AC2)
* SCT Error Recovery Control (AC3)
* SCT Features Control (AC4)
* SCT Data Tables (AC5)
Security:
Master password revision code = 65534
supported
not enabled
not locked
frozen
not expired: security count
supported: enhanced erase
128min for SECURITY ERASE UNIT. 128min for ENHANCED SECURITY ERASE UNIT.
Logical Unit WWN Device Identifier: 5000cca67fd1b206
NAA : 5
IEEE OUI : 000cca
Unique ID : 67fd1b206
Checksum: correct
/dev/sda:
ATA device, with non-removable media
Model Number: Hitachi HTS725050A9A364
Serial Number: *****************
Firmware Revision: PC4OC70E
Transport: Serial, ATA8-AST, SATA 1.0a, SATA II Extensions, SATA Rev 2.5, SATA Rev 2.6; Revision: ATA8-AST T13 Project D1697 Revision 0b
Standards:
Used: unknown (minor revision code 0x0028)
Supported: 8 7 6 5
Likely used: 8
Configuration:
Logical max current
cylinders 16383 16383
heads 16 16
sectors/track 63 63
--
CHS current addressable sectors: 16514064
LBA user addressable sectors: 268435455
LBA48 user addressable sectors: 976773168
Logical/Physical Sector size: 512 bytes
device size with M = 1024*1024: 476940 MBytes
device size with M = 1000*1000: 500107 MBytes (500 GB)
cache/buffer size = 15151 KBytes (type=DualPortCache)
Form Factor: 2.5 inch
Nominal Media Rotation Rate: 7200
Capabilities:
LBA, IORDY(can be disabled)
Queue depth: 32
Standby timer values: spec'd by Vendor, no device specific minimum
R/W multiple sector transfer: Max = 16 Current = 16
Advanced power management level: 128
Recommended acoustic management value: 128, current value: 254
DMA: mdma0 mdma1 mdma2 udma0 udma1 udma2 udma3 udma4 udma5 *udma6
Cycle time: min=120ns recommended=120ns
PIO: pio0 pio1 pio2 pio3 pio4
Cycle time: no flow control=120ns IORDY flow control=120ns
Commands/features:
Enabled Supported:
* SMART feature set
Security Mode feature set
* Power Management feature set
* Write cache
* Look-ahead
* Host Protected Area feature set
* WRITE_BUFFER command
* READ_BUFFER command
* NOP cmd
* DOWNLOAD_MICROCODE
* Advanced Power Management feature set
Power-Up In Standby feature set
* SET_FEATURES required to spinup after power up
SET_MAX security extension
Automatic Acoustic Management feature set
* 48-bit Address feature set
* Device Configuration Overlay feature set
* Mandatory FLUSH_CACHE
* FLUSH_CACHE_EXT
* SMART error logging
* SMART self-test
* General Purpose Logging feature set
* WRITE_{DMA|MULTIPLE}_FUA_EXT
* 64-bit World wide name
* IDLE_IMMEDIATE with UNLOAD
* WRITE_UNCORRECTABLE_EXT command
* {READ,WRITE}_DMA_EXT_GPL commands
* Segmented DOWNLOAD_MICROCODE
* Gen1 signaling speed (1.5Gb/s)
* Gen2 signaling speed (3.0Gb/s)
* Native Command Queueing (NCQ)
* Host-initiated interface power management
* Phy event counters
* NCQ priority information
Non-Zero buffer offsets in DMA Setup FIS
DMA Setup Auto-Activate optimization
Device-initiated interface power management
In-order data delivery
* Software settings preservation
* SMART Command Transport (SCT) feature set
* SCT LBA Segment Access (AC2)
* SCT Error Recovery Control (AC3)
* SCT Features Control (AC4)
* SCT Data Tables (AC5)
Security:
Master password revision code = 65534
supported
not enabled
not locked
frozen
not expired: security count
supported: enhanced erase
128min for SECURITY ERASE UNIT. 128min for ENHANCED SECURITY ERASE UNIT.
Logical Unit WWN Device Identifier: 5000cca67fd1b206
NAA : 5
IEEE OUI : 000cca
Unique ID : 67fd1b206
Checksum: correct
■電源モード状態の確認
# hdparm -C /dev/sda
/dev/sda:
drive state is: active/idle
/dev/sda:
drive state is: active/idle
■ディスクジオメトリ（シリンダ数/ヘッダ数/セクタ数) デバイスセクタ数、オフセット表示
# hdparm -g /dev/sda
/dev/sda:
geometry = 60801/255/63, sectors = 976773168, start = 0
/dev/sda:
geometry = 60801/255/63, sectors = 976773168, start = 0
■読み込み速度測定（ディスクアクセスは無し、バッファキャッシュから直接読み出す）
# hdparm -T /dev/sda
/dev/sda:
Timing cached reads: 3012 MB in 2.00 seconds = 1506.39 MB/sec
/dev/sda:
Timing cached reads: 3012 MB in 2.00 seconds = 1506.39 MB/sec
■読み込み速度測定（ディスクアクセス有り、バッファキャッシュ経由で読み出す））
# hdparm -t /dev/sda
/dev/sda:
Timing buffered disk reads: 298 MB in 3.00 seconds = 99.30 MB/sec
/dev/sda:
Timing buffered disk reads: 298 MB in 3.00 seconds = 99.30 MB/sec
以上、
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