31 July 2011 C1 CIVIL AVIATION DEPARTMENT HONG KONG ...

central database of software programs) that store should be:(i)subject to configuration control processes.NOTE: ED-12B/DO-178B provides criteria for such a process by definingthe configuration control process's objectives as:Configuration items are identified.Baselines and traceability are established.Problem reporting, change control, change review, andconfiguration status accounting are established.Archive, retrieval, and release are established.Software load control is established.Software life cycle environment control is established.(ii)appropriately isolated from the rest of the network to preventunauthorised access or contamination from viruses. Thisisolation can be achieved using a series of access controlfunctions and firewalls. However, protecting a networkedsystem against viruses is a complex issue and considerationshould be given to this store being separated from the network.(d)An appropriate number of backups should be maintained utilisingstandard software backup techniques.1.3 FLS and DFLD Receipt ProceduresSpecific procedures implemented for the receipt of FLS and DFLD that aretransferred using electronic distribution techniques should give considerationto the following:(a)(b)(c)(d)(e)That the FLS or DFLD has come from an appropriate source and thatsufficient configuration control processes are in place to ensure that thecorrect data and/or executable code will be supplied.That they are accompanied by suitable release documentation.That a record of purchase is created.That suitable controls are in place to prevent use of FLS and DFLDthat have become corrupted during its existence in any "open"environment, such as on the Internet.That means are provided to allow detection of corruption.30 September 2005 AN-43 A1 P.2