Administrace komentářů

Ahoj, po zjištění, že potíže s UDF se naštěstí týkají pouze CD-RW, mám tentokrát hardwarový dotaz. Koupil jsem si externí vypalovačku Samsung. Udávané rychlosti zápisu jsou:

• DVD±R: 22
• DVD+RW: 8
• DVD-RW: 6
• DVD+R DL: 16
• DVD-R DL: 12
• DVD-RW DL: 2
• DVD-RAM: 12

Rychlosti jsou uvedeny v násobcích 1350 kB/s, jak bývá zvykem.

Problém je jednoduchý: Při zápisu na DVD+RW s UDF dosahuji rychlosti 250 kB/s. To je (mírně řečeno) hodně nepříjemné.

Tedy jednoduchá otázka: Co bych mohl mít špatně? Snad něco z tohoto...?

# sdparm --all --long /dev/sr0       
    /dev/sr0: TSSTcorp  CDDVDW SE-S224Q   TS00  [cd/dvd]
Read write error recovery [rw] mode page:               
  AWRE        0  [cha: y, def:  0]  Automatic write reallocation enabled
  ARRE        0  [cha: n, def:  0]  Automatic read reallocation enabled 
  TB          0  [cha: n, def:  0]  Transfer block                      
  RC          0  [cha: n, def:  0]  Read continuous                     
  EER         0  [cha: n, def:  0]  Enable early recovery               
  PER         0  [cha: y, def:  0]  Post error                          
  DTE         0  [cha: n, def:  0]  Data terminate on error             
  DCR         0  [cha: y, def:  0]  Disable correction                  
  RRC       128  [cha: y, def:128]  Read retry count                    
  COR_S       0  [cha: n, def:  0]  Correction span (obsolete)          
  HOC         0  [cha: n, def:  0]  Head offset count (obsolete)        
  DSOC        0  [cha: n, def:  0]  Data strobe offset count (obsolete) 
  EMCDR       0  [cha: n, def:  0]  Enhanced media certification and defect reporting
  WRC         0  [cha: n, def:  0]  Write retry count                                
  ERTL        0  [cha: n, def:  0]  Error reporting threshold length (blocks)        
Write parameters (MMC) [wp] mode page:                                               
  BUFE        0  [cha: y, def:  0]  Buffer underrun free recording enable            
  LS_V        0  [cha: n, def:  0]  Link size valid                                  
  TST_W       0  [cha: y, def:  0]  Test write                                       
  WR_T        0  [cha: y, def:  0]  Write type                                       
  MULTI_S     0  [cha: y, def:  3]  Multi session                                    
  FP          1  [cha: y, def:  0]  Fixed packet type                                
  COPY        0  [cha: y, def:  0]  Serial copy management system (SCMS) enable
  TRACK_M     7  [cha: y, def:  5]  Track mode
  DBT        10  [cha: y, def:  8]  Data block type
  LINK_S      0  [cha: n, def:  0]  Link size
  IAC         0  [cha: y, def:  0]  Initiator application code
  SESS_F     32  [cha: y, def:  0]  Session format
  PACK_S     32  [cha: y, def:  0]  Packet size
  APL       150  [cha: y, def:150]  Audio pause length (blocks)
Protocol specific logical unit [pl] mode page:
  LUPID       0  [cha: n, def:  0]  Logical unit's (transport) protocol identifier
Power condition [po] mode page:
  IDLE        1  [cha: n, def:  1]  Idle timer active
  STANDBY     1  [cha: n, def:  1]  Standby timer active
  ICT       2780  [cha: n, def:2780]  Idle condition timer (100 ms)
  SCT       6000  [cha: n, def:6000]  Standby condition timer (100 ms)
Informational exceptions control [ie] mode page:
  PERF        0  [cha: n, def:  0]  Performance (impact of ie operations)
  EBF         0  [cha: n, def:  0]  Enable background function
  EWASC       0  [cha: n, def:  0]  Enable warning
  DEXCPT      0  [cha: n, def:  0]  Disable exceptions
  TEST        0  [cha: n, def:  0]  Test (simulate device failure)
  EBACKERR    0  [cha: n, def:  0]  Enable background (scan + self test) error reporting
  LOGERR      0  [cha: n, def:  0]  Log informational exception errors
  MRIE        0  [cha: n, def:  0]  Method of reporting informational exceptions
  INTT        0  [cha: n, def:  0]  Interval timer (100 ms)
  REPC        0  [cha: n, def:  0]  Report count (or Test flag number [SSC-3])
Timeout and protect (MMC) [tp] mode page:
  G3E         0  [cha: n, def:  0]  Group 3 timeout capability enable
  TMOE        0  [cha: n, def:  0]  Timeout enable
  DISP        0  [cha: n, def:  0]  Disable (unavailable) until power cycle
  SWPP        0  [cha: n, def:  0]  Software write protect until power cycle
  G1MT        6  [cha: n, def:  6]  Group 1 minimum timeout (sec)
  G2MT        0  [cha: n, def:  0]  Group 2 minimum timeout (sec)
CD/DVD (MM) capabilities and mechanical status (MMC) [cms] mode page:
  D_RAM_R     1  [cha: n, def:  1]  DVD-RAM read
  D_R_R       1  [cha: n, def:  1]  DVD-R read
  D_ROM_R     1  [cha: n, def:  1]  DVD-ROM read
  METH2       1  [cha: n, def:  1]  Method 2
  CD_RW_R     1  [cha: n, def:  1]  CD-RW read
  CD_R_R      1  [cha: n, def:  1]  CD-R read
  D_RAM_W     1  [cha: n, def:  1]  DVD-RAM write
  D_R_W       1  [cha: n, def:  1]  DVD-R write
  TST_WR      1  [cha: n, def:  1]  Test write
  CD_RW_W     1  [cha: n, def:  1]  CD-RW write
  CD_R_W      1  [cha: n, def:  1]  CD-R write
  BUF         1  [cha: n, def:  1]  Buffer underrun free recording
  MULT_S      1  [cha: n, def:  1]  Multi session
  M2F2        1  [cha: n, def:  1]  Mode 2 form 2
  M2F1        1  [cha: n, def:  1]  Mode 2 form 1
  DP_2        0  [cha: n, def:  0]  Digital port 2
  DP_1        0  [cha: n, def:  0]  Digital port 1
  COMP        0  [cha: n, def:  0]  Composite
  AUDIO_P     1  [cha: n, def:  1]  Audio play
  RBC         0  [cha: n, def:  0]  Read bar code
  UPC         1  [cha: n, def:  1]  Uniform product code
  ISRC        1  [cha: n, def:  1]  International standard recording code
  C2PS        1  [cha: n, def:  1]  C 2 pointers supported
  RW_DC       1  [cha: n, def:  1]  R-W de-interleaved and corrected
  RW_S        1  [cha: n, def:  1]  R-W supported
  CDDA_SA     1  [cha: n, def:  1]  CD-DA stream accurate
  CDDA_CS     1  [cha: n, def:  1]  CD-DA commands supported
  LMT         1  [cha: n, def:  1]  Loading mechanism type
  EJECT       1  [cha: n, def:  1]  Eject (individual or magazine)
  PJ          0  [cha: n, def:  0]  Prevent jumper
  LS          1  [cha: n, def:  0]  Lock state
  LOCK        1  [cha: n, def:  1]  Lock (supported)
  RWILI       1  [cha: n, def:  1]  R-W in lead in
  SCC         0  [cha: n, def:  0]  Side change capable
  SSS         0  [cha: n, def:  0]  Software slot selection
  CSDP        0  [cha: n, def:  0]  Changer supports disc present
  SCM         1  [cha: n, def:  1]  Separate channel mute
  SVL         1  [cha: n, def:  1]  Separate volume levels
  MRSS      16620  [cha: n, def:8467]  Maximum read speed supported (kBps) (obs)
  NVLS      256  [cha: n, def:256]  Number of volume levels supported
  BSS       2048  [cha: n, def:2048]  Buffer size supported (1024 bytes)
  LENGTH      1  [cha: n, def:  1]  Length (bit length of IEC958 words)
  LSBF        0  [cha: n, def:  0]  LSB (least significant bit) first
  RCK         0  [cha: n, def:  0]  High on LRCK indicates left channel
  BCKF        0  [cha: n, def:  0]  BCK signal falling edge
  CMRS        1  [cha: n, def:  1]  Copy management revision supported
  RCS         0  [cha: y, def:  0]  Rotation control selected
  CWSS      5540  [cha: n, def:  0]  Current write speed selected

Poslední řádka výpisu je zajímavá. Zvolená rychlost zápisu (je-li v kB/s) přibližně odpovídá čtyřnásobné rychlosti. To je jistě správné, protože médium DVD+RW, na které vypaluji, má toto omezení. Jenže proč je pak skutečná rychlost nějakých 250 kB/s? Pochopil bych, kdyby se dosahovalo například poloviny slibované rychlosti, ale tohle by měl i hlemýžď dávno vypálené!

Připomínám, že se jedná o externí vypalovačku. Tedy nejspíš není v mé moci nějak ovlivňovat použití cache a další parametry typické pro IDE. Write caching mám vypnutý, protože jeho použití se nedoporučuje. (Zatím neumí detekovat vadné médium.) Co bych měl tedy zkusit nastavit?