ADFSDB mapping

Table 1. Structure SDBBLOCK
`Offset Dec`	`Offset Hex`	`Type`	`Len`	`Name(Dim)`	`Description`
`0`	`(0)`	`STRUCTURE`	`64`	`SDBBLOCK`	`STREAM DESCRIPTOR BLOCK`
`0`	`(0)`	`CHARACTER`	`4`	`SDBIDEN`	`"SDB" IN EBCDIC`
`4`	`(4)`	`CHARACTER`	`8`	`SDBNAME`	`NAME OF THIS STREAM`
`LOGICAL LINE NUMBER POINTERS`
`12`	`(C)`	`UNSIGNED`	`4`	`SDBLLNB`	`BASE LLN`
`16`	`(10)`	`UNSIGNED`	`4`	`SDBOLDN`	`LLN OF OLDEST LINE`
`20`	`(14)`	`UNSIGNED`	`4`	`SDBCURN`	`LLN OF NEWEST LINE`
`GET AND PUT ROUTINE ADDRESSES`
`24`	`(18)`	`ADDRESS`	`4`	`SDBGET`	`ADDRESS OF GET ROUTINE`
`28`	`(1C)`	`ADDRESS`	`4`	`SDBPUT`	`ADDRESS OF PUT ROUTINE`
`32`	`(20)`	`ADDRESS`	`4`	`SDBCLOS`	`ADDRESS OF CLOSE ROUTINE`
`36`	`(24)`	`SIGNED`	`4`	`SDBLEN`	`LENGTH OF SDB AND FOLLOWING SDX`
`40`	`(28)`	`CHARACTER`	`4`	`*`
`40`	`(28)`	`CHARACTER`	`1`	`SDBCLASS`	`STREAM CLASS`
`41`	`(29)`	`UNSIGNED`	`1`	`SDBTYPE`	`STREAM TYPE: 0=EXTRA,1=INPUT, 2=OUTPUT`
`42`	`(2A)`	`CHARACTER`	`2`	`*`	`RESERVED`
`44`	`(2C)`	`UNSIGNED`	`4`	`SDBPOSN`	`LLN NEXT TO BE FETCHED`
`48`	`(30)`	`UNSIGNED`	`4`	`SDBFLAGS`
		`1... ....`		`SDBNOWRP`	`STREAM IS NOT TO WRAP`
		`.1.. ....`		`SDBALARM`	`SOUND ALARM WITH NEW DATA`
`48`	`(30)`	`BIT(30) POS(3)`	`4`	`*`	`RESERVED BITS`
`52`	`(34)`	`SIGNED`	`4`	`SDBAVL(3)`	`RESERVED`
`64`	`(40)`	`CHARACTER`	`0`	`SDBAREA`	`AREA FOR SYSTEM DEPENDENT INFO`