those are auto backups of the recording-dump file, which is a complete dump of your recorded programs.
It used to only generate one but it was decided that many backups would be more useful.
You could probably write something to play with it if you wanted difference behaviour.
AMD FM1 x4 A8-3870 Llano, Gigabyte GA-A75-D3H, 4 Gb DDR3 Ram, Seagate 500 Gb, Seagate 1500 Gb, HVR3000 x 2 (DVB-S), Nova-T 500 (DVB-T), USB-Uirt, SPDIF -> Yamaha RX-V540, ATI HD6550 (OnBoard) > Samsung LA46A650 TV (HDMI), Harmony Remote 525
Windows 7 Ultimate x64 SP1, NPVR 2.4.3, AC3Filter, 1 x Popcorn Hour A-100, 1 x AppleTV with Plex