At this time, since the computer is began along with the hard disk isn't recognized, the contents with the really hard disk 0 cylinder 0 head 1 sector can still be read out by utilizing DOS Debug around the A disk or the drive disc, and right after modification, create 0 cylinder 0 head 1 fan Area, restarting the machine is no dilemma. When you modify the partition table parameters to other parameters at random, you can use the system disk with DOS installed to begin when you can not get started it. Pressing
sony video camera data recovery software free download , you could not load the prompt with the DOS command interpreter COMMAND, The system crashed. Even so, a floppy disk or boot CD formatted as a program disk can be started successfully. Provided that there's Debug, you are able to still modify the partition table parameters back. If sadly, the partition table parameters are changed to a circular chain, that is definitely, the following partition in the C drive points to the D drive, along with the next partition of your D drive points to the C drive. This cycle continues, because the logical drive is read endlessly at startup, so Will crash. At this time, so long as there's a really hard disk, the computer system cannot be started no matter the floppy disk or the really hard disk. The failure to start is as a result of the really hard disk. Even though the hard disk is installed on one more laptop or computer, it can't be applied, to ensure that the hard disk is fully locked. A full really hard disk lock system, nevertheless it would be to rewrite the boot system of 0 cylinder 0 head 1 sector, and destroy the partition table or intentionally develop a circular partition table, and put the true challenging disk partition table parameters and boot program in other Hide sectors and guard them. In the event the password isn't appropriate at startup, the pc cannot be began, and in the event the password is right, the pc begins successfully. This type of hard disk lock plan is often began using a boot disk within a great predicament. The really serious circumstance is that the boot disk cannot be started. At this time, the hard disk is locked.
three.five.2 Quite a few frequent unlocking approaches 1. 'Hot plug' tough disk energy supply. 'Hot plug' tough drive power will be to not power around the locked challenging drive when the technique is started, then 'hot plug' the power cord after the boot is completed, to ensure that the method can control the difficult drive usually. 2. U1traEdit very first prepares a startup disk, then makes use of a binary editing tool (U1traEdit is suggested) on other normal computers to modify the 10.SYS file on the floppy disk (ahead of the modification, modify the file's attributes to normal). Especially, search for the initial '55AA' string in this file and modify it to any other value following locating it. With this modified system floppy disk, you'll be able to successfully boot together with the locked challenging disk, but at this time, simply because the regular partition table of your difficult disk has been destroyed, once you can't use Fdisk to delete and modify the partition, you are able to make use of the partition table Recovery method to cope with. 3. DMDM is a disk management tool that will carry out high-level formatting, low-level formatting, data zeroing, repartitioning, backing up partition tables, and testing disks. It can be a really valuable tool. It supports all current new hard disk technologies and has really potent functions: quickly, uncomplicated and sophisticated solutions, novice customers can quickly master the hard disk installation function, and may completely meet the unique desires of advanced users; fully help the FAT32 supported by the user operating system File method. Format a drive bigger than 2GB on a partition. When customers use the sophisticated installation mode or menu mode, they are able to decide on the size on the disk cluster they need to have; break the 8.4GB and 32GB limits; use the challenging disk diagnostic function in the hard disk subsystem Identify interrelated difficulties; compatible with a number of operating systems, which includes Windows9X / ME / NT4 / 2000 / DOS / OS / 2; support IDE power management; incorporates multi-sector study and write assistance for IDE / ATA drives to accelerate information Transfer; Promptly format IDE / ATA / SCSI drives. In most circumstances, the totally installed drive doesn't exceed 1min; supports high-speed data transfer of enhanced IDE / FASTATA; the low-level formatter included in it's far more sophisticated than the low-level formatter integrated with quite a few BI-OS. It can modify the interleaving element in the tough disk, and in some cases repair some tough disks that have problems with track 0. For the reason that DM is usually a really hard disk tool that does not depend on the motherboard BIOS to recognize the difficult disk, even when the difficult disk is set to 'NONE' inside the motherboard BIOS, the DM can recognize the tough disk and perform partitioning and formatting operations, so you can also make use of the DM software program to unlock the challenging disk .Very first copy the DM to a method disk, connect the locked difficult disk and boot up, press the 'Delete' crucial to enter the BIOS settings, set all IDE interfaces to 'NONE' and save and exit, then use the floppy disk to start the system, the technique You'll be able to start with 'lock', due to the fact the technique is equal to no really hard disk at this time. Just after starting, run DM. When the DM can recognize the hard disk, pick the hard disk to format the partition. This approach is basic and practical, but there is one particular The fatal shortcoming is the fact that the data around the tough disk can not be kept. When employing DM, the use mode implies: / m: Manualmode. (Manual mode switch) /c.Colormode (color display mode) / p: PC-XT mode / a : PC-AT mode / 2: DOS2.XXmode (make DM operate in DOS2.XX mode) / 3: DOS3.XXmode (make DM function in DOS3.XX mode) / 4: DOS4, XXmode (make DM work in DOS4.XX Mode operate) / z: Zen let hMS -DOScompadbil let ymode (make use of the maximum compatibility mode of MS-DOS when DM works) / w: WyseMS-DOScompadbil uninstall mode (make DM compatible with WyseMS-DOS) / I enable DM to make use of NECDOS3's large partition function mode underNECDOS3.3Only / v : VariableClusterandrootdirectorySizes (modify the size in the cluster and also the number of root directories with DM) / 0: OperatediSklllallageranddeViCedriveruSlngversiOn2.02conventions (make the DM work with the version 2.02 device driver) / i: SelectinterleavevalueduringautomactiCinstallaon (with hard drive crossover element) Don't use default parameters / s: Sectorpertrackparametermatching (choose the number of tracks in the sector) / five: UseWD1005styletranslationscheme (make DM work with WD1005 transmission scheme) / 7: USeWD1007StyletransladonSCheme (make DM operate with WD1007 transmission scheme) / k; specifycytinderSkewandheadSkewforusedUringlowlevelinitialization (DM Forced cylinder and head offset) / d: Enterbytes-fromindex (BFI) whenAddingnawstothedefectlist (BFI is employed when the DM enters the defect list. Way) four. The strategy of unlocking the hard disk lock The root result in of challenging disk lock would be the IO.SYS file in DOS. It includes 4 modules: LOADER, 101, 102, and 103. Among
dv images , 101 contains a essential plan, Syslnt-I. It have to very first study the partition table through startup. If the partition table is encountered in a loop, it'll only crash, which is a really serious defect of DOS. Recognizing that the bring about lies in DOS, you are able to control the partition table not to be read throughout the startup method, even the difficult disk just isn't read, and you can commence successfully. In actual fact, the method of realizing the program of unlocking the really hard disk is usually to rewrite a set of applications and save it within the startup disk to start. Through the computer's startup method, in the event you choose to start from the hard disk, the laptop and disk will initially study the contents of tough disk 0 cylinder 0 head 1 sector into memory 0000: 7C00, and jump to 0000: 7C00 to execute. Should you choose to boot from a floppy disk, the pc and the disk will initially study the contents of A disk 0 flux 0 head 1 sector into the memory at 0000: 7C00, and jump to 0000: 7C00 to execute. During the execution course of action, the laptop does not Check what the content material of your sector is, and only execute the study command mechanically, so that quite a few systems can survive the virus. But employing this, the system unlocking approach is just right. In the event you format a system floppy disk that will start the machine with DOS, move the contents of track 0, head 0, and sector 1 on the soft surface towards the blank fan in the back. Within the area, and re-write a system to the 0 track, 0 head, and 1 sector of your floppy disk, to ensure that when the floppy disk is started, the system written prior to is executed initial. Within this program, it has some functions: preemptively intercept INT13H just before DOS starts, reside in high-end memory and monitor INT13H, decide no matter if to read the hard disk, if it can be to study the hard disk, return straight towards the similar, in order that the reading on the hard disk is prohibited. It avoids the crash attributable to DOS reading the difficult disk circular partition table; in the exact same time, it intercepts the reading on the floppy disk. If reading the 0 track, 0 head and 1 sector of your floppy disk, it will likely be changed to read the sector with all the real boot plan and disk parameter table, avoiding DOS Could not uncover the disk parameter table of your floppy disk through startup. When completing these tasks, it's necessary to read the genuine boot program of the floppy disk and give it manage. This system could be referred to as a versatile, mainly because it does not deal with the tough disk throughout booting with a floppy disk, so no matter what technique the really hard disk utilizes to lock, it has no effect on DOS startup. Needless to say, the computer system started within this way does not recognize the difficult disk, but this will not matter. After the pc starts, you may use Debug to get in touch with up the new INT13H plan that resides in high-end memory, and adjust it to only one particular statement that directly executes the old INT13H, so that you are able to use INT12H to study challenging disk 0 cylinder 0 head 1 sector under Debug If there's a backup, right after the partition table parameters are restored, write 0 cylinder 0 head 1 sector, and restart the pc. If there is no backup, remove the circular chain in the partition table and restart the personal computer with all the normal DOS boot disk to at the very least re-partition the difficult disk in order that the tough disk is locked and can't be opened. five. Procedures and description ① The following is the supply system important.com stored within the floppy disk or optical disk 0 track 0 head 1 sector, the program is input by Debug. 0> debug-a100100CH101XORAX, AX103MOVDS, AX105MOVES, AX107MOVSS, AX109MOVAX, 7000100MOVSP, AX10ESTI10FMOV, SI, AX111MOVDI, 7E00114CLD115MOVCX, 0200118REPNZ119MOVSB11AJMP0000; 7ElF11FMOVCX, 0003122PISHCX123MOVAX, 0201; floppy disk boot sector read enable 126MOVBX, 7000129MOVCX, 4F0112CMOVDX, 010012FINT13131POPCX132DECCX133JNX0122135MOVAX, [0040] Be the first to have the location of INT13H 138MOV [7E88], AX13BMOVAX, [004E] 13EMOV [7E8A], AX141MOVAX, [0413] 144DECAX145MOV [0413], AX148MOVCL, 0614ASHLAX, CL14CMOVES, AX14EXORAX, AX150MOVDS, copy AX152MOVSI, 7E6, 7E6 Memory 155MOVDI, 0000158MOVCX, 003015BREPNZ015CMOVSB015DMOVAX, 0000; create new INT13H place to interrupt vector table 0160MOV [004C], AX0163MOVAX, ES0165MOV [004E], AX0168JMP0000: 7C00016DPUSHF: new INT13H plan 016ECMPDX, 0080; regardless of whether it is actually challenging disk 0172 0174POPF0175IRET; if it can be a tough disk, it returns straight to 0176CMPDX, +00. Do you study the floppy disk BOOT region? 0179JNZ0186017BCMPCX, + 01017EJNZ01860180MOVCX, 4F01; yes, study 79 tracks, 1 head, 1 sector, 0183MOVDX, 01000186POPF0187JMP0000: 0000; here, jump to execute the old INT13, the position of your INT13H on the f day is written by the earlier program and written in to the Nkey, comRCX200WQ ② program. Ahead of proceeding to the following perform, initially create a boot disk, test the contents of the boot disk in to the CD, and after that use Debug. key.com transfers the system essential.com towards the memory offset address of 100H, and writes the segment loading plan at 400H, that may be, C> debugkey.com-a400400MOVCX, 0003403PUSHCX404MOVAX, 0201; study the A disk boot plan into the 1000H 407MOVBX, 1000; so as to assure achievement, the first use of repeated reading 40AMOVCX, 000140DMOV.DX, 0000410INT13412POPCX
413DECCX
414JNZ0403
416MOVAX, 0301; write the floppy disk boot program that has been study in to the floppy disk
419MOVBX, 1000; the initial sector from the last track
41CMOVCX, 4F01
41FMOVDX, 0100
422INT13
424MOVAX, 0301; create crucial.com system to floppy disk 0 track 0 head 1 sector
427MOVBX, 0100
42AMOVCX, 0001
42DMOVDX, 0000
430INT13
432INT3
So that you can make sure foolproof, the contents in the two sectors with the boot disk really should be read out once more to make sure right writing. After booting in the floppy disk, the difficult disk just isn't recognized, as well as the new INT13H system resides inside the high-end memory. This program is really part of key.com from 16D to 187. Because of the existence of this plan, the difficult disk can't be study below Debug, along with the hard disk partition table can't be restored. Consequently, this program should be modified following the pc is began. This system is located at 9FCO: 0000 in memory. Under Debug, use U9FCO: 0 to display this system. It may be observed that a jump instruction is located at 9FCO.001A, as well as the jump instruction is transferred to execute the original INT13H. Due to the fact the BIOS version is distinctive, the place of your jump instruction could be various. At this time, write a statement below Debug: a9FCO: 03MPF000: A5D4. Within this way, the create prohibition and study prohibition in the challenging disk no longer function. Below Debug, the partition table from the challenging disk could be read out using the subfunction two of INT13H. Just after the modification is restored, the information is written back for the partition table with all the subfunction three Exit Debug and restart the computer with DOS.
six. Recommend
To better safeguard the difficult disk, it's most effective to back up the tough disk partition table information. There are actually two techniques to back up, one particular is to retailer the partition data of each and every logical disk from the difficult disk within the form of a file; the other is to back up the partition info within the hidden sector in the challenging disk. By way of example, you'll be able to back up 0 cylinder 0 head 1 sector in 0 cylinder 0 head 3 sector, and start disk D with cylinder number 0 head 1 sector within this cylinder 0 head 3 sector, other logical disks also in this way. This process is easy, hassle-free, and trustworthy.