Nhung dieu nen biet khi format o dia cung

Thứ hai, 01 Tháng tám 2011, 12:30 GMT+7


Format (dinh dang) dia la qua trinh chuan bi o dia cung, dia mem hay USB de luu tru du lieu. Trong mot so tinh huong, format dia cung tao ra mot hay mot vai he thong luu tru file (file system). Tuy theo tung yeu cau ma co the thuc hien viec dinh dang nay o cap thap hoac cap cao.

Format cap thap


Format cap thap (LLF – Low Level Format) la viec dinh dang lai cac track (ranh tu), sector (cung tu), cylinder (lien cung tu) cua o dia cung. Cac hang san xuat o dia cung thuong thuc hien format cap thap lan dau tien truoc khi xuat xuong cac o dia cung. Nguoi su dung chi nen dung cac phan mem cua chinh hang san xuat de format cap thap (cung co cac phan mem cua hang khac nhung co the cac phan mem nay khong nhan biet dung cac thong so cua o dia cung khi tien hanh dinh dang lai va do do co the gay ra cac van de khong luong truoc duoc).

Qua trinh format cap thap se dinh dang o cung vat ly thanh mot o cung duy nhat thong qua cac buoc:

+ Ra soat cac sector, danh dau cac bad sector (cung tu loi) neu co.

+ Xoa thong tin trong MBR (Master Boot Record - ban ghi khoi dong chinh).

+ Dinh dang bang MFT (Master File Table - chua thong tin ve cac track va cac sector cua o cung).

Format cap thap co 2 loai:

Loai thu nhat su dung cac chuong trinh Console trong moi truong DOS. Khi do qua trinh format se thuc hien cac buoc nhu tren, nhung khong thuc hien gan gia tri 0 vao moi cung tu (fill-zero). Vi vay neu su dung loai format nay thi du lieu van co the cuu duoc bang cac cong cu chuyen nghiep.

Loai thu hai su dung chuc nang LLF (Low Level Format) cua BIOS. Ngoai nhung buoc thuc hien nhu tren, chuc nang LLF se vua doc cac cung tu tren o cung, vua dien gia tri 0 vao moi cung.

Format cap thap se loai tru cac bad sector. Do vay moi lan thuc hien LLF dung luong o cung co the bi giam di mot chut khi dia co nhung cung tu bi loi vat ly.


Nhung dieu nen biet khi format o dia cung
Format o cung la mot qua trinh quan trong (Nguon anh: Internet)

Format cap cao

Format cap cao (High-level Format) la cac hinh thuc format thong thuong ma nhieu nguoi su dung da tung thuc hien (chung duoc goi ten nhu vay de phan biet voi format cap thap) boi cac lenh san co trong DOS hoac Windows. Hinh thuc format nay co hai dang: Quick format va Full format.

Quick format: la qua trinh dinh dang chi don thuan xoa thong tin trong bang MFT, de he dieu hanh hoac cac phan mem co the ghi de du leu moi len cac du lieu cu. Neu thuc hien quick format trong DOS, ban co the su dung lenh format voi tham so "/q". Neu thuc hien quick format trong he dieu hanh Windows, ban chi viec chon "Quick Format" trong muc Format options.

Quick format khong phat hien va loai bo cac bad sector. Do do quick format thuong duoc su dung khi nguoi dung cai moi he dieu hanh Windows, hoac loai bo nhanh chong cac du lieu cu tren o dia.

Full format: la qua trinh dinh dang dien ra giong quick format, nhung se doc tat ca cac track trong o cung logic do, dong thoi danh dau sector bi loi (neu co). Nhu vay full format se xoa bo cac du lieu cu, dong thoi kiem tra, phat hien va danh dau loai bo nhung vung dia bi hu hong, tranh viec tiep tuc ghi du lieu vao cac vung dia da bi hu hong nay.


Nhung dieu nen biet khi format o dia cung
Giao dien format o cung


Tham so khi format

O dang format cap thap, ban hau nhu khong phai nhap tham so gi khi thuc hien thao tac trong moi truong DOS.

O dang format cap cao, neu la hinh thuc quick format thi cac thong so duoc giu nguyen nhu lan format gan nhat. Co mot thong so ma nguoi tien hanh format can can nhac lua chon la kich thuoc cua don vi luu tru co ban: Cluster.

Kich thuoc cluster co the lua chon bat dau tu 512 bytes, tuong duong voi kich thuoc cua don vi luu tru nho nhat: sector (1 sector = 512 bytes). Cac kich thuoc con lai co the la 1024, 2048, 4096 bytes.

Su lua chon kich thuoc cluster phu thuoc chu yeu vao viec ban su dung phan vung can dinh dang de luu tru cac tap tin co kich thuoc nhu the nao. Chung ta cung xem vi du sau de hieu hon ve lua chon kich thuoc cluster. Neu lua chon kich thuoc cluster la 512 bytes thi khi luu mot file dung luong 100 bytes, tren o dia cung se phai dung den it nhat 1 cluster (512 byte) de chua tap tin nay. Khi do phan dung luong bi bo phi khong su dung la 412 bytes. Nhung neu lua chon kich thuoc cluster la 4096 bytes thi phan dung luong bi bo phi khong su dung se thanh 3996 bytes. Tuy nhien, neu lua chon kich thuoc cluster co kich thuoc nho thi cac bang FAT (File Allocation Table) hoac cac bang MFT (Master File Table) lai tro nen lon hon.

Nhu vay, neu de luu tru cac file van phong nhu Word, Excel..., ban co the chon kich thuoc cluster la 1024 hoac 2048 bytes. Nguoc lai neu luu tru cac file la cac bo cai dat phan mem hoac cac file video co kich thuoc lon, ban co the chon kich thuoc cluster lon hon.

Windows co the cho ban biet kich thuoc thuc (size) cua mot file va kich thuoc chiem dung cua file do tren o cung (size on disk) bang cach bam chuot phai va chon Properties. Khi nhin vao 2 thong so nay, ban se de dang nhan ra su lang phi neu tren.

Tren day la nhung thong tin co ban ban nen biet khi tien hanh format o cung. Nhung thong tin nay se giup ban lua chon duoc hinh thuc format phu hop voi muc dich su dung.

Chuc cac ban thanh cong.

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