关于u盘的描述符问题

我用usb viewer 看u盘描述符，得到下面的结果。
奇怪的是为什么只有一个bulk in端点和一个控制端点？
不是应该还有一个bulk out端点吗？
那位大虾给解释一下。
Device Descriptor:
bcdUSB:             0x0110
bDeviceClass:         0x00
bDeviceSubClass:      0x00
bDeviceProtocol:      0x00
bMaxPacketSize0:      0x08 (8)
idVendor:           0x0DD8
idProduct:          0x1003
bcdDevice:          0x0200
iManufacturer:        0x01
iProduct:             0x02
iSerialNumber:        0x00
bNumConfigurations:   0x01

ConnectionStatus: DeviceConnected
Current Config Value: 0x01
Device Bus Speed:     Full
Device Address:       0x02
Open Pipes:              2

Endpoint Descriptor:
bEndpointAddress:     0x81
Transfer Type:        Bulk
wMaxPacketSize:     0x0040 (64)
bInterval:            0x00

Endpoint Descriptor:
bEndpointAddress:     0x00
Transfer Type:     Control
wMaxPacketSize:     0x0507 (1287)
wInterval:          0x0202
bSyncAddress:         0x40

这位大侠功力好深，可以修改usb view！
看到了，两个bulk，一个interrupt端点。
用的传输协议是bulk only。
命令栈是scsi transparent command set。

我现在正在看scsi reduce commamd block set。
不知道跟前者是否兼容？

我把USBVIEW改了一下，你再试试，我测试的结果如下，测试时请打开菜单“设置\\config...”，然后刷新一下
Device Descriptor:
bcdUSB:             0x0110
bDeviceClass:         0x00
bDeviceSubClass:      0x00
bDeviceProtocol:      0x00
bMaxPacketSize0:      0x40 (64)
idVendor:           0x0EA0
idProduct:          0x6803
bcdDevice:          0x0100
iManufacturer:        0x01
0x0409: \"USB\"
iProduct:             0x02
0x0409: \"Solid state disk\"
iSerialNumber:        0x03
0x0409: \"3B011B083E153AB0\"
bNumConfigurations:   0x01

ConnectionStatus: DeviceConnected
Current Config Value: 0x01
Device Bus Speed:     Full
Device Address:       0x02
Open Pipes:              3

Endpoint Descriptor:
bLength:              0x07
bDescriptorType:      0x05
bEndpointAddress:     0x81
bmAttributes:         0x02
wMaxPacketSize:       0x40
bInterval:            0x00
>>Transfer Type:      Bulk
wMaxPacketSize:     0x0040 (64)
bInterval:            0x00

Endpoint Descriptor:
bLength:              0x07
bDescriptorType:      0x05
bEndpointAddress:     0x02
bmAttributes:         0x02
wMaxPacketSize:       0x40
bInterval:            0x00
>>Transfer Type:      Bulk
wMaxPacketSize:     0x0040 (64)
bInterval:            0x00

Endpoint Descriptor:
bLength:              0x07
bDescriptorType:      0x05
bEndpointAddress:     0x83
bmAttributes:         0x03
wMaxPacketSize:       0x02
bInterval:            0x01
>>Transfer Type: Interrupt
wMaxPacketSize:     0x0002 (2)
bInterval:            0x01

Configuration Descriptor:
bLength:              0x0009
bDescriptorType:      0x0002
wTotalLength:         0x0027
bNumInterfaces:       0x01
bConfigurationValue:  0x01
iConfiguration:       0x00
bmAttributes:         0x80
MaxPower:             0x32
bmAttributes:         0x80 (Bus Powered )
MaxPower:             0x32 (100 mA)

Interface Descriptor:
bLength:              0x09
bDescriptorType:      0x09
bInterfaceNumber:     0x00
bAlternateSetting:    0x00
bNumEndpoints:        0x03
bInterfaceClass:      0x08
bInterfaceSubClass:   0x06
bInterfaceProtocol:   0x50
iInterface:           0x00

bInterfaceSubClass:   0x06
bInterfaceProtocol:   0x50
iInterface:           0x00

Endpoint Descriptor:
bLength:              0x07
bDescriptorType:      0x05
bEndpointAddress:     0x81
bmAttributes:         0x02
wMaxPacketSize:       0x40
bInterval:            0x00
>>Transfer Type:      Bulk
wMaxPacketSize:     0x0040 (64)
bInterval:            0x00

Endpoint Descriptor:
bLength:              0x07
bDescriptorType:      0x05
bEndpointAddress:     0x02
bmAttributes:         0x02
wMaxPacketSize:       0x40
bInterval:            0x00
>>Transfer Type:      Bulk
wMaxPacketSize:     0x0040 (64)
bInterval:            0x00

Endpoint Descriptor:
bLength:              0x07
bDescriptorType:      0x05
bEndpointAddress:     0x83
bmAttributes:         0x03
wMaxPacketSize:       0x02
bInterval:            0x01
>>Transfer Type: Interrupt
wMaxPacketSize:     0x0002 (2)
bInterval:            0x01