Linfo displays system statistics such as disk space usage, network usage, hardware information, mounted file systems, hard drives, RAM, hostname, uptime, etc. The Linux version works by parsing the /proc and /sys filesystems and also by connecting to daemons such as hddtemp for determining physical health.
The Exquisite `df' (xdf) is a souped-up version of df(1) rewritten from scratch and focused on flexibility of field selection and output format. It offers HTML and CSV outputs, besides the traditional text-based console output. It is fit for system administrators who are tired of post-processing df(1) output through shell or Perl scripts in order to avoid broken lines or to get a simple total/summary line.
sdb is a really simple program to benchmark disks. It only writes/reads data sequentially to/from a file and calculates the performance of this action. A memory buffer is used for input/output to get values close to the real performance of the disk or RAID system. You can use flags like O_DIRECT and O_SYNC to avoid buffering by the operating system. It is similar to dd, but there are some differences, since dd was not created for benchmarking a disk. It is possible to initialize the buffer with random values before writing them to the disk or a file on the disk. It is a simple but effective program to get the maximum speed of a disk. Due to the simplicity, you will get the results much faster than with a more complex benchmark.
DiskScan scans the entire surface of a disk, alerts when a sector is unreadable, and uses the read timing to warn when a sector is having problems. It will tell when a disk has failed and already has bad sectors and also when the disk is near failure and takes too long to read the data.
Gpart is a small tool which tries to guess which partitions are on a PC harddisk in case the primary partition table was damaged. It works by scanning through the device (or file) given on the commandline on a sector basis. Each guessing module is asked if it thinks a filesystem it knows about could start at a given sector. Several filesystem guessing modules are built in, and others can be added dynamically.