Попытка стереть содержимое диска, заполнив все биты цифрой «1», а не «0»
У меня есть 2 старых диска WD объемом 160 ГБ, у которых нет опции «Security-Delete» при запросе с помощью hdparm.
Я понимаю нынешнее признание механизма перезаписи дисков нулями.
ССЫЛКА: Надежно ли удаляет файлы при заполнении диска dd?
Но это оставляет желать лучшего.
Разве не было бы лучше иметь механизм, такой как / dev / one, для создания потока из них?
Разве максимальная намагниченность на дорожке не лучше, чем попытка удалить это намагничивание? Или это похоже на попытку достичь уровня 6 сигм, когда 3/4-сигма - это все, что могут измерить современные технологии?
С этой целью, как мне сформулировать мою команду для генерации потока "все биты на" для заполнения блока размером 512 байт?
-1
задан Eric
25 January 2021 в 21:17
Ссылка
2 ответа
Спасибо Halfgaar за то, что направил меня на badblocks. Это был идеальный путь к тому, чего я хотел достичь.
Для моего домашнего рабочего стола эта задача, выполненная таким образом, заняла бы около 54+ часов без перерыва.
Здесь я привожу скрипт, который я создал для решения своих задач. Объяснения причин включены в сценарий.
#!/bin/sh
BASE=`basename "$0" ".sh" `
TRACKER=./${BASE}.last
SLICE=`expr 4096 \* 16 `
echo "\n\t This utility will overwrite the full disk with all data bits ON\n\t using '0xFFFF' as test pattern for destructive badblocks scan ..."
echo "\n\t This utility will begin at the last sector and work its way towards the first sector\n\t on the disk, doing slices of ${SLICE} sectors at one time ..."
echo "\n\t The design concept is based on fact that some older USB-attached devices\n\t have both slow interface and slow disk I/O, as well as taking into account\n\t the End-User context of a Desktop computer which cannot remain up and running\n\t for 2-3 days non-stop. The process can be interrupted at any time and\n\t the script will be able to restart at the last known completed segment\n\t to continue from there."
if [ "$1" != "--force" ]
then
echo "\n\n\t As a security precaution, you MUST review the script to ensure proper\n\t understanding of DANGERS AND RISKS before proceeding.\n Bye!\n" ; exit 1
fi
echo "\n\t Enter disk (block) device path (i.e. /dev/sdb) => \c" ; read DISK
if [ -z "${DISK}" ] ; then echo "\n\t No path entered for a block device. Cannot proceed.\n Bye!\n" ; exit 1 ; fi
if [ ! -b "${DISK}" ] ; then echo "\n\t '${DISK}' is not an existing block device file. Cannot proceed.\n Bye!\n" ; exit 1 ; fi
testor=`df | grep ${DISK} | head -1 `
if [ -n "${testor}" ] ; then echo "\n\t Mounted partitions for that device:" ; echo "${testor}" | awk '{ printf("\t\t %s\n", $0 ) ; }' ; echo " Bye!\n" ; exit 1 ; fi
### Disk /dev/sdd: 149.5 GiB, 160041885696 bytes, 312581808 sectors
SECTORS_LGCL=`fdisk -l ${DISK} | grep '^Disk '${DISK} | awk '{ print $7 }' `
echo "${SECTORS_LGCL}" | awk '{ printf("\t SECTORS_LOGICAL = %12s\n", $0 ) ; }'
### Sector size (logical/physical): 512 bytes / 4096 bytes
SECT_SIZE_LGCL=`fdisk -l ${DISK} | grep '^Sector size' | awk '{ print $4 }' `
SECT_SIZE_PSCL=`fdisk -l ${DISK} | grep '^Sector size' | awk '{ print $7 }' `
CLUMPING=`expr ${SECT_SIZE_PSCL} / ${SECT_SIZE_LGCL} `
SECTORS_PSCL=`expr ${SECTORS_LGCL} / ${CLUMPING} `
echo "${SECTORS_PSCL}" | awk '{ printf("\t SECTORS_PHYSICAL = %12s\n", $0 ) ; }'
LAST_TODO=0
LAST=`expr ${SECTORS_PSCL} - 1 `
ITERATION=`expr ${LAST} - ${SLICE} + 1 `
COUNT=`expr ${SECTORS_PSCL} / ${SLICE} `
if [ -s ${TRACKER} ]
then
read ITERATION <${TRACKER}
ITERATION=`expr ${ITERATION} - ${SLICE} `
echo "\t Using last known good ITERATION captured before last abandon ..."
COUNT=`expr ${ITERATION} - 1 ` ; COUNT=`expr ${COUNT} / ${SLICE} `
fi
echo "\t Iteration countdown from $COUNT ..."
while [ ${ITERATION} -ge ${LAST_TODO} ]
do
echo "${COUNT} ${ITERATION} ${SECTORS_PSCL}" | awk '{ printf("\n\n[%s] Slice 1st sector = %12s / %s ...\n", $1, $2, $3 ) ; }'
ITERATION_LAST=`expr ${ITERATION} + ${SLICE} - 1 `
if [ ${ITERATION_LAST} -gt ${SECTORS_PSCL} ]
then
ITERATION_LAST=`expr ${SECTORS_PSCL} - 1 `
ITERATION=`expr ${ITERATION_LAST} - ${SLICE} `
fi
echo "${ITERATION_LAST}" | awk '{ printf("\tITERATION_LAST = %12s\n", $0 ) ; }'
echo "${SLICE}" | awk '{ printf("\tSLICE = %12s\n", $0 ) ; }'
echo "${ITERATION}" | awk '{ printf("\tITERATION = %12s\n", $0 ) ; }'
badblocks -v -s -w -b ${SECT_SIZE_PSCL} -p 0 -e 0 -t 0xFFFF /dev/sdd ${ITERATION_LAST} ${ITERATION}
echo "${ITERATION}" >${TRACKER}
if [ ${ITERATION} -eq ${LAST_TODO} ]
then
break
else
ITERATION=`expr ${ITERATION} - ${SLICE} `
if [ ${ITERATION} -lt ${LAST_TODO} ]
then
ITERATION=${LAST_TODO}
fi
fi
COUNT=`expr ${COUNT} - 1 `
done
exit
Вывод сессии (после повторного запуска) выглядит так:
This utility will overwrite the full disk with all data bits ON
using '0xFFFF' as test pattern for destructive badblocks scan ...
This utility will begin at the last sector and work its way towards the first sector
on the disk, doing slices of 65536 sectors at one time ...
The design concept is based on fact that some older USB-attached devices
have both slow interface and slow disk I/O, as well as taking into account
the End-User context of a Desktop computer which cannot remain up and running
for 2-3 days non-stop. The process can be interrupted at any time and
the script will be able to restart at the last known completed segment
to continue from there.
Enter disk (block) device path (i.e. /dev/sdb) => /dev/sdd
SECTORS_LOGICAL = 312581808
SECTORS_PHYSICAL = 312581808
Using last known good ITERATION captured before last abandon ...
Iteration countdown from 4712 ...
[4712] Slice 1st sector = 308846247 / 312581808 ...
ITERATION_LAST = 308911782
SLICE = 65536
ITERATION = 308846247
Checking for bad blocks in read-write mode
From block 308846247 to 308911782
Testing with pattern 0xffff: done
Reading and comparing: done
Pass completed, 0 bad blocks found. (0/0/0 errors)
[4711] Slice 1st sector = 308780711 / 312581808 ...
ITERATION_LAST = 308846246
SLICE = 65536
ITERATION = 308780711
Checking for bad blocks in read-write mode
From block 308780711 to 308846246
Testing with pattern 0xffff: done
Reading and comparing: done
Pass completed, 0 bad blocks found. (0/0/0 errors)
***
0
Я придумал более прямой метод с использованием базовой команды dd, надеясь, что это ускорит процесс. К сожалению, хронометраж обоих методов показал, что они практически эквивалентны, оба колеблются в пределах 54+ часов.
Вот сценарий для метода 'dd':
#!/bin/sh
BASE=`basename "$0" ".sh" `
SEEDlocn="/site/DB003_F1"
TMP="${SEEDlocn}/${BASE}.bitsON"
ROOTlocn=`df / | grep '/dev/sd' | awk '{ print $1 }' `
testor=`df ${SEEDlocn} | grep '/dev/sd' | awk '{ print $1 }' `
if [ "${testor}" = "${ROOTlocn}" ] ; then echo "\n\t Disk for ${SEEDlocn} is not mounted. Unable to proceed.\n Bye!\n" ; exit 1 ; fi
echo "\n\t Following block devices have been identified:\n"
lsblk -l | awk '{ if( length($1) == 3 ){ print $0 } ; }' | awk '{ printf("\t\t %s\n", $0 ) ; }'
echo "\n\t Enter the block device's full path => \c" ; read DISK
if [ -z "${DISK}" ] ; then echo "\n\t Empty string.\n Bye!\n" ; exit 1 ; fi
echo "\n\t Enter the LABEL for the block device => \c" ; read LABEL
if [ -z "${LABEL}" ] ; then echo "\n\t Empty string. Need proper LABEL for unique tracking and safe/correct restart.\n Bye!\n" ; exit 1 ; fi
TRACKER="./${BASE}.${LABEL}.last"
testor=`df | grep ${DISK} `
if [ -n "${testor}" ] ; then echo "\n\t Drive is mounted on ${DISK} ... Cannot proceed.\n Bye!\n" ; exit 1 ; fi
testor=`stat ${TMP}.binaryBLOB | grep '^ Size:' | awk '{ print $2 }' `
if [ -z "${testor}" ] ; then testor="0" ; fi
if [ ${testor} -eq 1073741824 ]
then
echo "\n\t Using existing seed file '${TMP}.binaryBLOB' ..."
else
echo "\n\t Creating input to create 512 byte seed file with all bits ON ..."
### Seed file size = 512 * 8 = 4096 bytes
cat <<-EOF_EOF >${TMP}.seed
00000000: ffff ffff ffff ffff ffff ffff ffff ffff ################
00000010: ffff ffff ffff ffff ffff ffff ffff ffff ################
00000020: ffff ffff ffff ffff ffff ffff ffff ffff ################
00000030: ffff ffff ffff ffff ffff ffff ffff ffff ################
00000040: ffff ffff ffff ffff ffff ffff ffff ffff ################
00000050: ffff ffff ffff ffff ffff ffff ffff ffff ################
00000060: ffff ffff ffff ffff ffff ffff ffff ffff ################
00000070: ffff ffff ffff ffff ffff ffff ffff ffff ################
00000080: ffff ffff ffff ffff ffff ffff ffff ffff ################
00000090: ffff ffff ffff ffff ffff ffff ffff ffff ################
000000a0: ffff ffff ffff ffff ffff ffff ffff ffff ################
000000b0: ffff ffff ffff ffff ffff ffff ffff ffff ################
000000c0: ffff ffff ffff ffff ffff ffff ffff ffff ################
000000d0: ffff ffff ffff ffff ffff ffff ffff ffff ################
000000e0: ffff ffff ffff ffff ffff ffff ffff ffff ################
000000f0: ffff ffff ffff ffff ffff ffff ffff ffff ################
00000100: ffff ffff ffff ffff ffff ffff ffff ffff ################
00000110: ffff ffff ffff ffff ffff ffff ffff ffff ################
00000120: ffff ffff ffff ffff ffff ffff ffff ffff ################
00000130: ffff ffff ffff ffff ffff ffff ffff ffff ################
00000140: ffff ffff ffff ffff ffff ffff ffff ffff ################
00000150: ffff ffff ffff ffff ffff ffff ffff ffff ################
00000160: ffff ffff ffff ffff ffff ffff ffff ffff ################
00000170: ffff ffff ffff ffff ffff ffff ffff ffff ################
00000180: ffff ffff ffff ffff ffff ffff ffff ffff ################
00000190: ffff ffff ffff ffff ffff ffff ffff ffff ################
000001a0: ffff ffff ffff ffff ffff ffff ffff ffff ################
000001b0: ffff ffff ffff ffff ffff ffff ffff ffff ################
000001c0: ffff ffff ffff ffff ffff ffff ffff ffff ################
000001d0: ffff ffff ffff ffff ffff ffff ffff ffff ################
000001e0: ffff ffff ffff ffff ffff ffff ffff ffff ################
000001f0: ffff ffff ffff ffff ffff ffff ffff ffff ################
EOF_EOF
cat ${TMP}.seed
ls -l ${TMP}.seed
echo "\n\t Creating 512 byte seed file with all bits ON ..."
xxd -revert ${TMP}.seed >${TMP}.seedbinary
hexdump ${TMP}.seedbinary
ls -l ${TMP}.seedbinary
echo "\n\t Creating 2 Mbyte seed file ..."
i=4096 ### iterations will create 2 Mbyte file
while [ true ]
do
if [ ${i} -eq 0 ]
then
break
fi
cat ${TMP}.seedbinary
echo ".\c" >&2
i=`expr ${i} - 1 `
done >${TMP}.seedbinary2
echo ""
hexdump -n 512 ${TMP}.seedbinary2
ls -l ${TMP}.seedbinary2
echo "\n\t Creating 1 Gbyte seed file ..."
i=512 ### iterations will create 1 Gbyte file
while [ true ]
do
if [ ${i} -eq 0 ]
then
break
fi
cat ${TMP}.seedbinary2
echo ".\c" >&2
i=`expr ${i} - 1 `
done >${TMP}.binaryBLOB
echo ""
hexdump -n 512 ${TMP}.binaryBLOB
### 2097152 bytes
fi
ls -l ${TMP}.binaryBLOB
BS="1048576" ### 512 * 2048 bytes = 1 MByte
BLOB_SIZE="1073741824" ### 1 GBytes
SLICE_BLOCKS=`expr ${BLOB_SIZE} / ${BS} ` ### count of ${BS}-byte blocks for 1 GB file
MAX="160"
if [ -s ${TRACKER} ]
then
read SLICE <${TRACKER}
echo "\n\t TRACKER file indicates last completed slice was # ${SLICE}. Continuing with the next slice ..."
SLICE=`expr ${SLICE} + 1 `
else
SLICE=1
fi
REMAIN=`expr ${MAX} - ${SLICE} `
while [ true ]
do
START_BLOCK=`expr ${SLICE} - 1 `
START_BLOCK=`expr ${START_BLOCK} \* ${SLICE_BLOCKS} `
echo "\n\t [${REMAIN}] Doing slice ${SLICE} of ${MAX} ..."
COM="dd status=progress bs=${BS} if=${TMP}.binaryBLOB count=${SLICE_BLOCKS} seek=${START_BLOCK} of=${DISK} iflag=fullblock conv=notrunc,fdatasync oflag=dsync"
echo "\t ${COM} ..."
${COM}
RC=$?
date
if [ ${RC} -ne 0 ] ; then echo "\n\t ERROR encounted. RC = ${RC} ...\n Bye!\n" ; exit 1 ; fi
echo "${SLICE}" >${TRACKER}
SLICE=`expr ${SLICE} + 1 `
REMAIN=`expr ${REMAIN} - 1 `
done
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