In addition to two computers, you should have at least one and preferably two large drives to attach to the computer. You will want to save your collected materials somewhere other than on the search computer. A large disk drive is the ideal place. But since drives sometimes crash and the information on them cannot be recovered, having two drives which are mirrors to each other is the safest and most professional route. As Navy SEALS say about virtually every piece of gear: “one is none and two is one.”
Some people in the field believe storing the files in the cloud is a better answer. Cloud computing – storing your files on a mainframe somewhere else – probably is safe and the stored material is backed up so there is relatively little chance of loss.
However, any time you store material with someone else you are sending it through a system where it can be intercepted and traced back to you. If you are gathering sensitive information – whether for government or a private concern – you want to reduce the chance of interception to zero. Cloud computing, for Open Source researchers, is less secure than keeping your collection of downloaded material on your own disk drives. Of course, to prevent loss through fire, flood, theft or other disasters you will want to keep your disk drives stored apart from one another.
The size of the external drives you select will depend on how much material you plan to collect and store over how long a period.Your storage needs will depend in part on what kind of material you are collecting. You will usually need less storage capacity when collecting text articles than you will need if you are collecting multi-media files, for instance. For most current collection needs, professionals find that external drives of 500 Megabytes to 5 Terrabytes are sufficient, These allow for growth of the collection over time.