Hard drive in a server except the hard drive happens to be installed in a remote chassis.
Data is typically stored on device in fixed sized blocks (eg. 512 Bytes).
Accessed by operating system as mounted drive volume.
Applications / file systems decide how blocks are combined and accessed.
Data is stored without any higher-level metadata. e.g. for data format type or ownership.
You can place any kind of file system on block level storage.
e.g. Windows uses NTPS, VMware uses VMFS.
Commonly deployed in Storage Area Network (SAN) storage.