Following is more detail of what I get with "show slots ts3310". The slots are not empty.
tsm: TSMOND>show slots ts3310
PVR slot information for library TS3310.
Library : TS3310
Product Id : 3576-MTL
Support module : 4
Mount count : 1
Drives : 2
Slots : 126
Changers : 1
Import/Exports : 6
Device : /dev/smc0
Drive 0, element 256
Drive 1, element 257
Changer 0, element 1
ImpExp 0, element number 16
ImpExp 1, element number 17
ImpExp 2, element number 18
ImpExp 3, element number 19
ImpExp 4, element number 20
ImpExp 5, element number 21
Slot 0, status Allocated, element number 4096, barcode not present, barcode value <>, devT=LTO, mediaT=427, elemT=ANY
Slot 1, status Allocated, element number 4097, barcode not present, barcode value <>, devT=LTO, mediaT=427, elemT=ANY
Slot 2, status Allocated, element number 4098, barcode not present, barcode value <>, devT=LTO, mediaT=427, elemT=ANY
Slot 3, status Allocated, element number 4099, barcode not present, barcode value <>, devT=LTO, mediaT=427, elemT=ANY
Slot 4, status Allocated, element number 4100, barcode not present, barcode value <>, devT=LTO, mediaT=427, elemT=ANY
Slot 5, status Allocated, element number 4101, barcode not present, barcode value <>, devT=LTO, mediaT=427, elemT=ANY
Slot 6, status Allocated, element number 4102, barcode not present, barcode value <>, devT=LTO, mediaT=427, elemT=ANY
.........
Slot 124, status Allocated, element number 4220, barcode not present, barcode value <>, devT=LTO, mediaT=427, elemT=ANY
Slot 125, status Allocated, element number 4221, barcode not present, barcode value <>, devT=LTO, mediaT=427, elemT=ANY