Sentence:  The Spectrum has its own inexpensive mass storage unit - the <WSD>microdrive</WSD> which starts at about £150 for 100k of storage, but this may not be suitable in all cases, since the storage unit may be damaged if turned on with the disc in position. 
Meaning of the word marked with <WSD> tags:  An early computer storage system using cartridges of looped tape.