the need for any intervening controller. External variants of these native drive protocols are extremely similar to the internal protocols, but are often expanded to carry power (such as eSATAp and the SCSI Single Connector Attachment) and to use a more durable physical connector. A host adapter with external port may be necessary to connect a drive, if a computer lacks an available external port. Direct attach serial interfaces USB or FireWire connections are typically used to attach consumer class external hard drives to a computer. Unlike SCSI, eSATA, or SAS these require circuitry to convert the hard disk's native signal to the appropriate protocol. Parallel ATA and internal Serial ATA hard disks are frequently connected to such chassis because nearly all computers on the market today have USB or FireWire ports, and these chassis are inexpensive and easy to find. Network protocols iSCSI, NFS, or CIFS are all commonly used protocols that are used to allow an external hard drive to use a network to send data to a computer system. This type of external hard drive is also known as Network-attached storage or NAS. Often, such drives are embedded computers running operating systems such as Linux or VxWorks that use their NFS daemons and SAMBA to provide a networked file system. A newer technology NAS, has been applied to some disk enclosures, which allows network ability, direct connection (e.g., USB) and even RAID features. Hard drive shucking "Shucking" refers to the process of purchasing an external hard disk drive and removing the drive from its enclosure, in order for it to be used as an internal disk drive. This is performed because external drives are often cheaper than internal drives of the same capacity and model, and that external drives designed for continuous usage often contain hard drives designed for increased reliability. Following the hard disk drive shortages caused by the 2011 Thailand floods, data storage company Backblaze reduced its cost of acquiring hard drives by purchasing external hard drives and shucking them. According to Backblaze Chief Executive Gleb Budman, the company purchased 1,838 external drives during this period. Describing the process as "drive farming", the company noted that it was much cheaper for them to purchase 3 TB external drives and removing them from their cases manually, than it is to purchase internal drives. See also Computer bus Computer case External storage Hard drive Network-attached storage Network