Комментарии 9
remap, badblock это не file system
Как например вы будите тестировать ремапы и бэд-ы на новом неформатированном диске?
Например с помощью Victoria, mhdd
Думаю для этого есть сервисная область\сервисная память
Наверное и на памяти есть что-то такое. Там же необязательно хранить много данных. Если уж 1000 ячеек вылетело — память лучше поменять.
В отличие от винчестера, реализация «ремапа» оперативной памяти довольно ресурсоёмка в железе т.к. всё должно работать на высоких скоростях.
Для повышения выхода годных могут делать небольшое количество "запасных строк" на каждую группу банков в чипах (DDR4 и LPDDR4), например
https://www.micron.com/~/media/documents/products/technical-note/dram/tn_4040_ddr4_point_to_point_design_guide.pdf
Post Package Repair (PPR): The Micron DDR4 SDRAM has one additional row available
for repair per bank (16 per x4/x8, eight per x16) even though JEDEC only requires one
additional row be available for repair per bank group (four per x4/x8, two per x16). PPR
enables the end user to replace one suspect row in each bank with one good spare row
https://www.google.com/patents/WO2017030564A1?cl=en "Newer memories, such as double data ram version 4 (DDR4) include so-called post-package repair (PPR) capabilities. PPR capabilities enable a compatible memory controller to remap accesses from a faulty row of a memory module to a spare row of the memory module that is not faulty."
https://www.micron.com/products/datasheets/%7B3D323C4D-6BC7-4193-908D-E99AD746AA4E%7D?page=12
JEDEC defines two modes of Post Package Repair (PPR): soft Post Package Repair (sPPR) and hard Post Package Repair (hPPR). sPPR is non-persistent so the repair row maybe altered; that is, sPPR is NOT a permanent repair and even though it will repair a row, the repair can be reversed, reassigned via another sPPR, or made permanent via hPPR. Hard Post Package Repair is persistent so once the repair row is assigned for a hPPR address, further PPR commands to a previous hPPR section should not be performed, that is, hPPR is a permanent repair; once repaired, it cannot be reversed. The controller provides the failing row address in the hPPR/sPPR sequence to the device to perform the row repair. hPPR Mode and sPPR Mode may not be enabled at the same time.
JEDEC states hPPR is optional for 4Gb and sPPR is optional for 4Gb and 8Gb parts… The JEDEC minimum support requirement for DDR4 PPR (hPPR or sPPR) is to provide one row of repair per bank group (BG), x4/x8 have 4 BG and x16 has 2 BG; this is a total of 4 repair rows available on x4/x8 and 2 repair rows available on x16.…
Soft post package repair (sPPR) is a way to quickly, but temporarily, repair a row element in a bank on a DRAM device, where hPPR takes longer but permanently repairs a row element. sPPR mode is entered in a similar fashion as hPPR, sPPR uses MR4[5] while hPPR uses MR4[13].
https://www.skhynix.com/static/filedata/fileDownload.do?seq=253 стр 169 "DDR4 supports Fail Row address repair as optional feature for 4Gb and required for 8Gb and above. Supporting PPR is identified via Datasheet and SPD in Module so should refer to DRAM manufacturer’s Datasheet. PPR provides simple and easy repair method in the system and Fail Row address can be repaired by the electrical programming of Electrical-fuse scheme." стр 172 "Soft Post Package Repair (sPPR) is a way to quickly, but temporarily, repair a row element in a Bank Group on a DDR4 DRAM
device, contrasted to hard Post Package Repair which takes longer but is permanent repair of a row element."
То есть мы имеем маргинальные преимущества по сравнению с софтовым решением. При этом софтовое решение универсальное и открытое, а аппаратное — vendor lock, проприетарное, эксклюзивное, патентованное и иным образом ограничивающее в возможностях применения.
Технология Dell Reliable Memory Technology PRO: обнаружение и изоляция ошибок памяти