What is it the HOT SWAP metod?


1. Introduction
Many HDDs store a part of managing microprogram on surfaces in a service area, and only loader is stored in ROM at the electronics. During initialization the program in ROM firstly tests main assemblies of HDD, initializes the microcircuits on card and then it loads resident part of the managing program and necessary configuration tables from service area of disks in RAM of microcontroller, therefore the microprogram completely gathers. Without this resident part of the microprogram the HDD can not execute the write/read of sectors, and as a result it can not write the service information if it is damaged! So, the HDDs can be divided into two groups:
1. First one includes the HDDs, which in case impossibility to read the information from a service zone information can be rewritten by program in ROM.
2. Second group includes the HDDs, in which the information from the service area cn no be rewritten by microprogram in ROM.

The first group includes the HDDs Western Digital Arch-0 .. Arch.IV, Fujitsu with Arch. MB9000 and the young families of Samsung.
The second includes Quantum, Maxtor, IBM, Seagate etc. To test or write the service information it is necessary to load the resident microprogram in RAM firstly. It can be made by two methodes : HOT SWAP (see further) and load the loader.
2. Loader.
Loader – is a resident microprogram, which is necessary to load in RAM of HDD to have the possibility to write the service area, which for any reasons is not read. It is obvious, that this program is written in codes of that microprocessor which is used in the given HDD.
For example, the HDD Quantum after cannot read a service zone, passes on a condition "save mode " in which it is possible with the help fo super commands to load in the RAM of the microcontroller the loader. To any other commands the HDD before loading the loader gives out the error ABRT. And the HDD WD after cannot read a service zone, commands read and write of service area carries out, therefore any loader for WD is not necessary. This is the same for the Fujitsu up to model MPF-AH inclusive. More in details about loading the loader look in the description of corresponding utilities.

3. Hot swap
Hot swap – is a methodics of loading the residental programming code, which is in modules of service area, in case the reading channel of HDD does not reading of any reasons from the service area (Bads in service area, damaging of heads, or damaging of service information etc.)

Hot swap -Hot swap uses when the HDD can not write the modules into service area without preliminary loading the modules. For example, HDDs QUANTUM or IBM can not write/read service area without preliminary loading from it modules with microprogramme and configuration. Another example, the HDDs WD can read/write/formatting service area, even if it is nothing reading from it and all necessary for this programmes are in ROM on pcb.


The main principle of Hot swap is you get operating HDD (donor) and launch it. Then you can command to stop spindel (this command is usual for almost any modern HDD and uses for transferting the HDD into the Safe mode) and without powering off turning off the platter of electronics. Then card is replacing into the HDD with damaged service area (recipient) and it is screwing. Now all necessary information for the work of HDD are in RAM and you can test service area, write or read the modules. But tables of translation are donor’s. That is why the data at the damaged HDD can be mixed or be partly damaged.
For this reason it is better to choose the HDD as donor-HDD with the minimum quantity of defects. Sometimes it is very useful to erase the table of defects of donor (of course to save resident table of defects previously to recover it later). After this the translator will be formed empty and possible shifts will replace only forward. This can make easier the recovery of the translator.

4. The methodic of usage of HOT-SWAP
First of all you should find proper donor. It is should be HDD with the same model, it should desirable be with the same version of microprogram (or as minimum the compatible). To check the compatibility it is necessary to remove the card of electronics from the recipient and place it on HDD donor. Then switch it on and make sure in full operability of the HDD. Then it is necessary from the donor with resident card (if it is possible) to read all service information: service, configuration modules configuration RAM (NV - RAM), main RAM etc, of course if it can be made by special utility of complex “PC-3000”. Only now you can start the hot swap:
1. Remove the card from the donor and put it aside, we will not use it more.
2. Remove the card from the recepient and install it to donor, screwing it with the main screws (as usual the screws which are fastened with the HDA).
3. Switch on the power of donor and wait the HDD go to the ready mode.
4. Launch special utility of the compex “PC-3000” (If there is no such utility to launch the universal utility ).
5. To give a command SLEEP, at this moment the HDD stop the spindel.
6. Not switching off the power turn off the screws, attaching the card and replace the card on HDA of recepient and fix the card with screws.
7. Now you can produce the checking а service area in “PC-3000” or try to recover data in “Data Extractor”. At the first given command the HDD should untwist the spindel and go to the ready mode.

ATTENTION!
After switchinf off the power you need to repeat the HOT SWAP.

Wow, thank you!

Thank you jerry.
This is very useful!

Why is everybody so surprised? This is from the manual that comes with pc3k.

I'm not seeing anybody surprised, I'm just thankful to jerry


And I never read that "pc3k manual", is this a quote from it?

I'm not surprised.
This is just the essencial of hdd recovery.
Those who want to do it still need to read the manual and study a lot.

tried it ! like a beginer ! study a lot ! like a beginer !
conclusions : others may talk about
1. if the heads are clicking the HS can`t do anything
2. be very carefull to write on the hdds who is good and who is bad
3. why the HS must be done TWICE ?
4. it works on hdds that enter BUSY state.

thanks
it was helpfull !

Study like a beginer and do not take conclusions too soon.

Do your home work and later start to figure out what can happen.

Do not generalize situations, this will not be the true.

With hard disk there is only one big true:
"There are 2 kind of hard disk, the one that stop and thouse that will stop."

Never fix what is not broken, this is also something that is good to remember.

Safe mode on Quantum HDD? How?

What Quantum? Newer if cannot read through, leave in SaveMode.

Hi ,

I have one questions :

What is someone doesn't have access to a utility like Pc3K for sending
the drive in STAND-BY MODE. Can he plug out the power cable of the
hdd.

regards

No, but...

MHDD

>stop

>exit

if you have autodetect enabled cause otherwise MHDD is going
to start up the motor again...