Never though I'm going to dive so deep in this Win32 rabbit hole.
I was originally thinking just wrote a simple wrapper of win32's tape API, but then I realized that the encryption is missing. With Win32's tape api, you can basically implement something like `/dev/st0` (simple read and write) amd `mt` command (rewind, seek, set compression, etc.). I was thinking just use LTOEnc for encryption control.
But that software can only read the encryption key from a file, which, to me, is a big security hole: I can do that in memory, why write to the disk temporarily?
So I start reading LTOEnc's code. I found Microsoft really don't want you to directly talk to SCSI. I read their documents, they never said about IOCTL_SCSI_PASS_THROUGH_DIRECT. They are recommending something like IOCTL_CDROM or something that is not so lower level.
Anyway, thanks to LTOEnc, and Oracle's helpdesk generously providing HPE product's tech ref manual, I now can implement the encryption control in my win32 lib. And soon I can do that in Java.
Several days ago I was suffering from jextract and the new project Panama things. Since it's new, there is not much useful documentation and can't get it work in a frustrating day. I was thinking maybe I'm not good at java stuff and should quit and become a Uber eat delivery guy or something. (I blame HR for those negative thoughts)
After several days of suffering and trying, I kind of know how it works and now I'm even writing win32 library in C++. I
m amazing 
@skyblond Are you working with LTO-related APIs at work or for fun? If I had some spare money, I'd love to get my hands on an LTO (maybe 4~5 gen) device.
@overflowcat 失业人士自娱自乐罢了（
我的磁带机是咸鱼买的。因为我的是笔记本，没有pcie插槽，咸鱼上正好有个大哥把雷电拓展坞和sas卡还有半高磁带机做成了一体的，用3d打印整了个盒子，我觉得挺简洁的。如果想自己搞的话，淘宝上有卖雷电转pcie和SAS/FC卡，根据需要自己拼就行了。
磁带机的话咸鱼上也有二手，如果资金充足（有三五万的预算）可以直接京东找HPE客服聊。我看他们说不要买IBM的磁带机，固件有计划报废而且毛病贼多。
@overflowcat 我买的是LTO 6，因为想一步到位。不然过几年换代的时候还要处理电子垃圾。不过LTO本身换代挺勤的，现在已经LTO 9了，而且向下兼容也缩减了。说好的30年存储，如果30年后没有能用的设备来读这些陈年磁带，那还不如不搞。
企业那边经常需要随着LTO标准更新换代，这样就有二手的廉价LTO磁带机。听说再过个两三年LTO 7的磁带机就该被换下来了。目前主流还是LTO 6，5代尚可接受（加密压缩全都有，还有LTFS），4代的话就只能用tar那种，没有LTFS支持。
Can't imagine now I'm writing C++ and using windows api. I almost reject everything that cannot run on JVM.
Yesterday I thought I'm going to give up during configure the project or compile with MSVC. But appallingly, I get it working and go those far.
Life is full of surprise.