A cartridge label tells us what might fit in the drive. It does not tell us how the recording was written, how a tape is blocked, which filesystem is present or what backup application wrote the bytes.
UNKNOWN MEDIA
│
IDENTIFY / PROTECT
│
MATCH TRANSPORT ── drive · firmware · interface · HBA
│
┌────┴────┐
TAPE BLOCK / FLUX
│ │
records sectors / transitions
└────┬──────┘
▼
RAW ACQUISITION → hash + preserve copy
│
LOGICAL IDENTIFY → tar · cpio · dump · FAT · HFS · UFS · LTFS · vendor set
│
FILE RECOVERYManufacturer, cartridge code, generation, capacity marking, write-protect state and source machine all matter. Similar shells can carry incompatible recordings. We photograph and record labels before handling the medium. Unknown media is not initialised, reformatted or used to test an unverified drive.
Older professional drives may require parallel SCSI: target IDs, termination, LVD versus single-ended operation, wide versus narrow buses, HBA firmware and cable quality all return. Other formats can require IDE/ATAPI, SATA, real floppy-controller hardware, USB bridges or specialised controllers.
Sequential tape contains records and filemarks. Backup applications can choose fixed or variable block sizes, write multiple tape files, span volumes and place their own metadata around the payload. We preserve that structure during acquisition.
BOT ─ [records] ─ FILEMARK ─ [records] ─ FILEMARK ─ [catalogue] ─ EOD
FreeBSD CAM and sa provide a mature SCSI tape environment through camcontrol, mt, /dev/sa0 and non-rewinding nodes. Linux complements it with st, lsscsi, SCSI-generic tools and broad bridge support.
For block-addressable magnetic and optical media, ddrescue is useful when sectors are unreliable. We do not apply disk-recovery assumptions to sequential tape.
After the physical recording is secure, we identify the logical structure. Straightforward cases include tar, cpio, Unix dump, FAT, HFS/HFS+, UFS, ISO 9660, UDF and LTFS. Commercial backup systems may expect catalogues, media databases, a particular version, encryption keys or other cartridges in the set.
Standard PC floppy disks can often be acquired as sectors. Unknown, damaged or non-PC disks may need flux-level capture instead. A flux image records magnetic transitions without forcing the disk through one assumed geometry or encoding.
Send clear photographs, labels and part numbers, plus anything known about the original computer or backup software.