AID_ISOLATED_START的用途是什么？

Question

在system / core / include / private / android_filesystem_config.h中，AID_ISOLATED_START的作用是什么？以及“完全隔离的沙盒进程的uid开始”是哪种情况？

#define AID_APP          10000  /* first app user */

#define AID_ISOLATED_START 99000 /* start of uids for fully isolated sandboxed processes */
#define AID_ISOLATED_END   99999 /* end of uids for fully isolated sandboxed processes */

这是从名称到ID的转换：

// Translate a user/group name to the corresponding user/group id.
// u0_a1234 -> 0 * AID_USER + AID_APP + 1234
// u2_i1000 -> 2 * AID_USER + AID_ISOLATED_START + 1000
// u1_system -> 1 * AID_USER + android_ids['system']
// returns 0 and sets errno to ENOENT in case of error
static unsigned app_id_from_name(const char* name) {
......