blah.c

#define REPS 200

// http://www.ioctls.net/
#define IOCTL_SCSI_PASS_THROUGH_DIRECT 0x4D014
#define SCSI_IOCTL_DATA_IN 1  // read data
#define SCSIOP_READ 0x28

typedef struct _SCSI_PASS_THROUGH_DIRECT
{
    USHORT Length;
    UCHAR ScsiStatus;
    UCHAR PathId;
    UCHAR TargetId;
    UCHAR Lun;
    UCHAR CdbLength;
    UCHAR SenseInfoLength;
    UCHAR DataIn;
    ULONG DataTransferLength;
    ULONG TimeOutValue;
    PVOID DataBuffer;
    ULONG SenseInfoOffset;
    UCHAR Cdb[16];
} SCSI_PASS_THROUGH_DIRECT, *PSCSI_PASS_THROUGH_DIRECT;

#pragma pack(push, scsi, 1)
typedef union _CDB
{
    struct _CDB10 {
        UCHAR OperationCode;
        UCHAR RelativeAddress : 1;
        UCHAR Reserved1 : 2;
        UCHAR ForceUnitAccess : 1;
        UCHAR DisablePageOut : 1;
        UCHAR Lun : 3;
        //UCHAR LBA[4];
        ULONG LBA;
        UCHAR Reserved2;
        //UCHAR TransferBlocks[2];
        USHORT TransferBlocks;
        UCHAR Control;
    } CDB10, *PCDB10;
} CDB, *PCDB;
#pragma pack(pop, scsi)

FILE_FS_SIZE_INFORMATION GetGeometry(ANSI_STRING dev_name)
{
    HANDLE handle;
    NTSTATUS status;
    IO_STATUS_BLOCK io_status;
    OBJECT_ATTRIBUTES obj_attr;
    FILE_FS_SIZE_INFORMATION size = {};

    InitializeObjectAttributes(&obj_attr, &dev_name, OBJ_CASE_INSENSITIVE, NULL, NULL);

    status = NtOpenFile(&handle, GENERIC_READ | SYNCHRONIZE, &obj_attr, &io_status, FILE_SHARE_READ, FILE_OPEN_FOR_FREE_SPACE_QUERY | FILE_SYNCHRONOUS_IO_NONALERT);
    if (!NT_SUCCESS(status)) {
        debugPrint("Couldn't open device for reading\n");
        return size;
    }

    NtQueryVolumeInformationFile(handle, &io_status, &size, sizeof(size), FileFsSizeInformation);
    NtClose(handle);

    debugPrint("%lld %lld %lu %lu\n", size.TotalAllocationUnits.QuadPart, size.AvailableAllocationUnits.QuadPart, size.SectorsPerAllocationUnit, size.BytesPerSector);
    Sleep(1000);

    return size;
}
void DoRawRead()
{
    NTSTATUS status;
    LARGE_INTEGER freq, start, end;
    PDEVICE_OBJECT pDevice;
    ULONG returnSize;

    ANSI_STRING name;
    char *abc = "\\Device\\CdRom0";
    RtlInitAnsiString(&name, abc);

    status = ObReferenceObjectByName(&name, 0, &IoDeviceObjectType, 0, (void**)&pDevice);
    if (!NT_SUCCESS(status)) {
        debugPrint("Couldn't open %s for reading\n", name.Buffer);
        goto cleanup;
    }

    FILE_FS_SIZE_INFORMATION geometry = GetGeometry(name);
    int size = 1 * geometry.BytesPerSector;
    int max_sectors = geometry.TotalAllocationUnits.QuadPart / 6;

    char *buffer = malloc(size + MAX_READ_SECTORS);
    if (!buffer) {
        debugPrint("Couldn't allocate buffer memory!\n");
        goto cleanup;
    }

    SCSI_PASS_THROUGH_DIRECT direct;
    memset(&direct, 0, sizeof(SCSI_PASS_THROUGH_DIRECT));
    direct.Length = sizeof(SCSI_PASS_THROUGH_DIRECT);
    direct.DataIn = SCSI_IOCTL_DATA_IN;
    direct.DataBuffer = buffer;
    direct.DataTransferLength = size;

    PCDB cdb = (PCDB)&direct.Cdb;
    cdb->CDB10.OperationCode = SCSIOP_READ;
    cdb->CDB10.ForceUnitAccess = 1;
    cdb->CDB10.LBA = __builtin_bswap32(0);
    cdb->CDB10.TransferBlocks = __builtin_bswap16(1);

    QueryPerformanceFrequency(&freq);
    for (int i = 0; i < REPS; i++) {
        if (__builtin_bswap32(cdb->CDB10.LBA) == max_sectors) {
            cdb->CDB10.LBA = __builtin_bswap32(0);
        } else {
            cdb->CDB10.LBA = __builtin_bswap32(max_sectors);
        }

        QueryPerformanceCounter(&start);
        status = IoSynchronousDeviceIoControlRequest(IOCTL_SCSI_PASS_THROUGH_DIRECT, pDevice, &direct, sizeof(SCSI_PASS_THROUGH_DIRECT), NULL, 0, &returnSize, FALSE);
        QueryPerformanceCounter(&end);

        if (!NT_SUCCESS(status)) {
            debugPrint("\nFailed. %lX\n", status);
            Sleep(10000);
            goto cleanup;
        } else {
            double speed = size * freq.QuadPart;
            speed /= (end.QuadPart - start.QuadPart);
            //speed /= 1000;
            //speed /= 1024; // KB/s is more useful than B/s

            debugPrint("Read Block: %lu %lu\n", (ULONG)speed, returnSize);
        }
    }

cleanup:
    free(buffer);
    debugPrint("Finished.\n");
    Sleep(10000);
}