1. UniVerse Hashed Files Internal Structure

2. Terminology Group –physical division Record –contains data Key –identifies record

3. Groups Group Modulo = number of groups

4. Groups Group Separation = size of groups (units of 512 bytes)

5. Groups Separation = 4 (group size 2K bytes) Group Header 2K Group 4K 6K8K10K12K14K0 Offset from beginning of file

6. Groups Separation = 4 (group size 2K bytes) Group Header 0x800 Group 0x1000 0x18000x20000x28000x30000x3800 0 Offset from beginning of file (reported in hex) as seen in LIST.READU

7. Primary Group Buffers Group Header 0x800 Group 0x1000 0x18000x20000x2800 0

8. Group Overflow Group Ovflw Header 0x800 Group 0x1000 0x18000x20000x28000x30000x3800 0

9. “Badly Overflowed” Group Ovflw Header 0x800 Group 0x1000 0x18000x20000x28000x30000x3800 0 Ovflw 0x4000

10. Where Files Break Group Ovflw Header 0x800 Group 0x1000 0x18000x20000x28000x30000x3800 0 Ovflw 0x4000 Files are most vulnerable on links between group buffers

11. Dynamic Files Group Header 0x800 Group 0x1000 0x18000x20000x2800 0 DATA.30 Ovflw Header 0x800 0 Ovflw 0x1000 OVER.30

12. Inside A Group Record Free Space

13. Inside A Group Record Free Space 0x2000 0x2164 0x2408 0x25a4 0x271b

14. … with Overflow Record Free Space Record Free Space 0x2000 0x2164 0x2408 0x25a4 0x271b 0xa8000 0xa8112 0xa82b0

15. UVFIXFILE : VLEVEL 4 : TRACE 4 Processing primary group: 4 0x00002000 F:0x0000203c B:0x0000003c (0x00000000) W:0x00020000 SIZE = 0x0000003c 0x0000203c F:0x000020c8 B:0x0000208c (0x00002000) W:0xc0300000 SIZE = 0x0000008c 0x000020c8 F:0x000020e0 B:0x00002024 (0x0000203c) W:0xc0300000 SIZE = 0x00000018 0x000020e0 F:0x00002134 B:0x0000209c (0x000020c8) W:0xc0300000 SIZE = 0x00000054 0x00002134 F:0x000021e0 B:0x0000204c (0x000020e0) W:0xc0300000 SIZE = 0x000000ac 0x000021e0 F:0x000021f8 B:0x0000212c (0x00002134) W:0xc0300000 SIZE = 0x00000018 0x000021f8 F:0x00002250 B:0x000021b8 (0x000021e0) W:0xc0100000 SIZE = 0x00000058 0x00002250 F:0x000022e0 B:0x00002168 (0x000021f8) W:0xc0100000 SIZE = 0x00000090 0x000022e0 F:0x00002330 B:0x00002200 (0x00002250) W:0xc0300000 SIZE = 0x00000050 0x00002330 F:0x00002384 B:0x000022b4 (0x000022e0) W:0xc0300000 SIZE = 0x00000054 0x00002384 F:0x000023ec B:0x00002358 (0x00002330) W:0xc0300000 SIZE = 0x00000068 0x000023ec F:0x000024a8 B:0x00002338 (0x00002384) W:0xc0300000 SIZE = 0x000000bc 0x000024a8 F:0x00000000 B:0x000020b4 (0x000023ec) W:0x20020000 SIZE = 0x00000358 >> Statistics for primary group 4. >> Used bytes = 1132 >> Free bytes = 916 >> Total bytes = 2048 Address of record Address of next record Backward link (BLINK) Record status bits Address of prev record Size of current record Address of record Address of next record

16. UVFIXFILE : VLEVEL 4 : TRACE 4 Processing primary group: 4 0x00002000 F:0x0000203c B:0x0000003c (0x00000000) W:0x00020000 SIZE = 0x0000003c 0x0000203c F:0x000020c8 B:0x0000208c (0x00002000) W:0xc0300000 SIZE = 0x0000008c 0x000020c8 F:0x000020e0 B:0x00002024 (0x0000203c) W:0xc0300000 SIZE = 0x00000018 0x000020e0 F:0x00002134 B:0x0000209c (0x000020c8) W:0xc0300000 SIZE = 0x00000054 0x00002134 F:0x000021e0 B:0x0000204c (0x000020e0) W:0xc0300000 SIZE = 0x000000ac 0x000021e0 F:0x000021f8 B:0x0000212c (0x00002134) W:0xc0300000 SIZE = 0x00000018 0x000021f8 F:0x00002250 B:0x000021b8 (0x000021e0) W:0xc0100000 SIZE = 0x00000058 0x00002250 F:0x000022e0 B:0x00002168 (0x000021f8) W:0xc0100000 SIZE = 0x00000090 0x000022e0 F:0x00002330 B:0x00002200 (0x00002250) W:0xc0300000 SIZE = 0x00000050 0x00002330 F:0x00002384 B:0x000022b4 (0x000022e0) W:0xc0300000 SIZE = 0x00000054 0x00002384 F:0x000023ec B:0x00002358 (0x00002330) W:0xc0300000 SIZE = 0x00000068 0x000023ec F:0x000024a8 B:0x00002338 (0x00002384) W:0xc0300000 SIZE = 0x000000bc 0x000024a8 F:0x00000000 B:0x000020b4 (0x000023ec) W:0x20020000 SIZE = 0x00000358 >> Statistics for primary group 4. >> Used bytes = 1132 >> Free bytes = 916 >> Total bytes = 2048 21e0 - 2134 = 00ac