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  • Removing power from harddisks without shutting down

    Hi, im running Xp pro on compact flash with EWF installed and working. However, i also have a second harddisk which contains all my large files on... this is writen to when i upload files via ftp.

    My question is, i know its ok to remove power from CF card as nothing is ever written to it. Is the same true for the harddisk? Surely windows is parking the harddisks for you when it shuts down? Or, do the disks have enough power stored when power is removed to park themselves?

    I take it a lot of people run systems like this with harddisks containing films/mp3s etc, would be interested to hear from people and if my concerns are valid.

    Thanks in advance,

    Chris

  • #2
    don't touch ide cables or power lead to a hard disk (whilst PC is on) unless you want to stuff it up and lose all your data!
    My Nissan 200SX @ Silverstone
    NOW SADLY WRITTEN OFF!

    My Car's spec list + pics

    Stealth CarPC fab'ing...

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    • #3
      CF cards don't take much power, don't bother to shut them down. It is possible to have the hard disks spin down and enter a low-power state under software control. Windows has some basic control built in by default (Display Properties -> Screen Saver -> Monitor Power (of all places, gotta love windoze!)) but there are some other apps that provide greater control.

      Windows will automagically spin the disk back up when it needs to access it.

      -p.

      Comment


      • #4
        Originally posted by g18c
        Hi, im running Xp pro on compact flash with EWF installed and working. However, i also have a second harddisk which contains all my large files on... this is writen to when i upload files via ftp.

        My question is, i know its ok to remove power from CF card as nothing is ever written to it. Is the same true for the harddisk? Surely windows is parking the harddisks for you when it shuts down? Or, do the disks have enough power stored when power is removed to park themselves?

        I take it a lot of people run systems like this with harddisks containing films/mp3s etc, would be interested to hear from people and if my concerns are valid.

        Thanks in advance,

        Chris
        just curious... but why do you wanna turn them off while your pc is still running?
        Pentium 4m 1.5GHz|MB896|Roadie Extreme|XM-Direct|Rikaline 6010|T-View 7"|Streetdeck|160gb Western Digital|1Gb DDR2-533 Ram

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        • #5
          Just get a Firewire external case for it... Problem solved!
          My Nissan 200SX @ Silverstone
          NOW SADLY WRITTEN OFF!

          My Car's spec list + pics

          Stealth CarPC fab'ing...

          Comment


          • #6
            sorry i didnt explain myself very well and people seem confused!!

            What i want is to remove power, ie turn the ignition off, so power is removed from the entire system at once.

            i have disabled write cache on the harddisk so as long as no data writes are taking place at time of power removal i presume no data loss will occur. i have looked into hardisks too and they autopark their heads when power is removed... got this from wikipedia

            Sound resonable?

            Chris

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            • #7
              Ok. I thought you meant to disconnect the drive whilst PC is running!

              Killing PSU power shouldn'tt do any harm as the PSU stores enough power to allow drives to park before being powered down...
              My Nissan 200SX @ Silverstone
              NOW SADLY WRITTEN OFF!

              My Car's spec list + pics

              Stealth CarPC fab'ing...

              Comment


              • #8
                Originally posted by g18c
                sorry i didnt explain myself very well and people seem confused!!

                What i want is to remove power, ie turn the ignition off, so power is removed from the entire system at once.

                i have disabled write cache on the harddisk so as long as no data writes are taking place at time of power removal i presume no data loss will occur. i have looked into hardisks too and they autopark their heads when power is removed... got this from wikipedia

                Sound resonable?

                Chris
                Do you have a shutdown controller? or are you just going to kill power?
                1990 Jeep Cherokee
                2000 VW Golf TDI 4dr
                2005 VW GTI MKIV - SOLD

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                • #9
                  Originally posted by g18c
                  sorry i didnt explain myself very well and people seem confused!!

                  What i want is to remove power, ie turn the ignition off, so power is removed from the entire system at once.

                  i have disabled write cache on the harddisk so as long as no data writes are taking place at time of power removal i presume no data loss will occur. i have looked into hardisks too and they autopark their heads when power is removed... got this from wikipedia

                  Sound resonable?

                  Chris
                  I have used that for years - never killed windows XP yet - just make
                  shure write cache is disabled - I dont use any shutdown controler at all
                  - I use a relay to turn a inverter off and on - the relay gets power
                  from the head unit - blue wire, it also turns my amp on

                  some day I will make a tank circuit - just to keep the computer running
                  for like 10-15 min - for truck stops, gas stations ect ect

                  Comment


                  • #10
                    I suppose the advantage with the blue wire is that when the car is running the blue wire is at 12v, then the engine is off its at 0v.

                    With the ignition wire you just get a _-_ pulse?
                    And there is no way to detect when the engine is turned off with the ignition wire?

                    Proposed carputer:

                    - Commell LV-650 mobo 128MB WinXP->CF
                    - Custom ctrl board (8ch ADC)
                    - Custom Delphi front end/hw ctrl software
                    - Mot M12 GPS (on COM1)+Maps
                    - 15" dash (non-inverter p/s hack)
                    - Remote control (IR to COM2)
                    - USB drive MP3 upload

                    Comment


                    • #11
                      Originally posted by Matthue
                      I suppose the advantage with the blue wire is that when the car is running the blue wire is at 12v, then the engine is off its at 0v.

                      With the ignition wire you just get a _-_ pulse?
                      And there is no way to detect when the engine is turned off with the ignition wire?

                      the blue wire has power when you turn the radio on, if you still
                      use the radio - if not then you would have to use the Accessory Wire
                      or any wire that has 12v with the car on, and use a switch and relay,
                      the relay connects to a 12v wire running from your battery to were
                      you need the power - the longer the wire the thicker it needs to be
                      and the switch turns the relay off and on -

                      but its just easy to use that blue wire - its run back to the trunk for
                      amps and power antennas, and shuts off with the radio - why run another
                      wire - just dont use that blue wire to power things, it might burn up your
                      radio

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                      • #12
                        Good! i'm going to create a web site to report on all my project progress, there I may post my recent circuit design for a startup/shutdown circuit

                        My circuit incorporates two transistors, a flip flop, logic inverter, 555 timer, another transistor to drive the relay and a I/O pin from the mobo to trigger the 555 timer with a programmable delay to shutdown the main power relay.

                        Proposed carputer:

                        - Commell LV-650 mobo 128MB WinXP->CF
                        - Custom ctrl board (8ch ADC)
                        - Custom Delphi front end/hw ctrl software
                        - Mot M12 GPS (on COM1)+Maps
                        - 15" dash (non-inverter p/s hack)
                        - Remote control (IR to COM2)
                        - USB drive MP3 upload

                        Comment

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