On Sat, Feb 16, 2013 at 11:07 PM, steve harley <[email protected]> wrote: > on 2013-02-14 16:47 Godfrey DiGiorgi wrote >> This is because iOS does not support external file systems, which >> cannot be sandboxed. A sandboxed file system promotes security and >> minimizes virus attacks, particularly important in mobile devices. > > iOS does support external file systems, just in specific limited ways; one > can copy certain types of files from an SD card _to_ an iOS device (which is > the direction with security implications), but not _from_ the iOS device > back to an SD card (or other storage)
Technically true, I'll give you that, but I meant/intended "generalized external file system support by the user." Sorry if I didn't type the whole thought out, I thought it was obvious. If you notice, the external file system support you illustrate is only read support, and only applies to external file system structures in the DCIM protocol model. To provide generalized user-level read/write support of an external file system would require directory system navigation, file and folder creation, file open, file write, and file close. This is not supported by any software that Apple supplies, at the user level. It can be achieved (with some effort) at the programming level. > at the same time, many iOS apps support bidirectional file transfer over > several network protocols and without the limits on file types that might > seem important for security reasons; this is a such a wide-open vector for > problem files to reach the device that it moots the idea that the SD card > restrictions are for security Apps read and write via wireless access only to their sandboxed local file systems. It's much easier to manage authentication and security via high-level wireless file exchange protocols. Access to an app's local file system within the iOS device has to be authenticated with permissions and signature certificates for exchange; this also promotes high security. Any intrusions into a local file system are restricted to that file system, they cannot act upon the OS or other application files. -- Godfrey godfreydigiorgi.posterous.com -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
