(b) archival purposes; or ­ (c) ­ the replacement of the lawfully owned copy of the computer programme in the event that the said copy of the computer programme is lost, destroyed or rendered unusable. (2) No copy or adaptation of a computer programme shall be used for any purpose other than those specified in subsection (1), and any such copy or adaptation shall be destroyed in the event that continued possession of the copy of the computer programme ceases to be lawful. (3) The authorisation of the lawful owner of a computer programme is not required where reproduction of the code and translation of its form are indispensable to obtain the information necessary to achieve the interoperability of an independently created computer programme with other programmes, unless the following conditions are satisfied — (a) ­ those acts are performed by the licensee or another person having a right to use a copy of a program; (b) ­ the information necessary to achieve interoperability has not previously been readily available; (c) ­ those acts are confined to the parts of the original program which are necessary in order to achieve interoperability. 23. � Visually impaired person (1) It shall be permitted, without the authorisation of the author or other owner of copyright, to reproduce a published work for persons who are blind, visually impaired or otherwise print disabled in an alternative manner or form which enables their perception of the work, and to distribute and make available the copies exclusively to those persons, where — (a) ­ the work is not reasonably available in an identical or largely equivalent form enabling its perception by these persons; and