
Hard Disk Drive Replacement Strategy:
Always try to run a  low-level format before replacing a  hard
disk drive.
 Attention 
The drive startup sequence in  the computer you are
servicing might have been changed. Be extremely
careful during write operations such  as copying,
saving, or formatting. Data  or programs can be
overwritten if you select an  incorrect drive.
How to Use Error  MessagesUse the error codes displayed  on the screen to diagnose
failures. If more than  one error code is displayed,  begin
the diagnosis with the first  error code. The cause  of the
first error code can result  in false error codes being
displayed. If no error  code is displayed, see if  the error
symptom is listed in the  Symptom-to-FRU Index for the
computer you are servicing.
How to Read POST  Error MessagesPOST error messages are displayed  on the screen as
three, four, five, or eight  digits. The error messages  that
can be displayed as shorter  POST messages are
highlighted in this index. Some digits will represent
different information for SCSI errors  versus non-SCSI
errors.
The following example shows which  digits display the
shorter POST error messages and  also defines the SCSI
information in an eight-digit error  message.
Shorter POST Messages
  ┌────┬────┬────┬────┐
│  │  │  │  │
  ┌────┬────┬────┬────┬────┬────┬────┬────┐
 │ ð│ ð│ ð│ ð│ ð│ ð│ ð│ ð│
  └────┴────┴────┴────┴────┴────┴────┴────┘
│  │  │  │  │  │  │  │
 Reserved ││││││Size (SCSI)
└────┴────┘  │  │ Slot Number (SCSI)
Device Code  │  Logical Unit Number (SCSI)
  ID (SCSI)
All SCSI devices are set  to a different SCSI ID.
Duplicate SCSI ID settings can  generate a false error
message. Use the SCSI  ID to determine whether the  error
message is coming from an  internal or an external device.
viii IBM Mobile Systems ThinkPad 310  (D/E/ED) HMM