认识RPi

Posted 2023-02-22 tommybjia

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篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了认识RPi相关的知识，希望对你有一定的参考价值。

一、实验目的和要求

1. 了解嵌入式板卡一般情况；

2. 熟悉pdDuino的供电等接线方式；

3. 复习Linux启动过程（操作系统课）；

4. 复习通过Linux获得硬件数据（操作系统课）；

5. 熟练掌握串口在PC上的使用；

6. 熟练掌握Linux的以太网和WiFi配置；

7. 熟练掌握Linux的SSH配置；

8. 熟练掌握PC上的SSH软件。

9. 掌握嵌入式板卡和PC建立文件共享的方式；

10. 寻找和安装交叉编译环境，理解交叉编译；

11. 熟悉嵌入式板卡的Linux下的编程环境；

12. 了解远程访问嵌入式板卡图形桌面的方式。

二、实验内容和原理

1. 在PC上安装好USB串口驱动和串口终端软件；

2. 按照图纸要求，将USB串口线与pcDuino连接好，并连接好以太网（如果打算采用WiFi，可不连接以太网）。如有条件，接上HDMI线和HDMI显示器；

3. 给pcDuino上电，记录启动过程的输出；

4. 从终端登陆pcDuino的Linux，配置网络和/或WiFi，从pcDuino和PC两端证明网络已连接；

5. 配置pcDuino的SSH，可尝试采用各种不同的认证方式；

6. 从PC通过SSH登陆pcDuino；

7. 看到多个不同端口的登陆（本机键盘/屏幕、串口和SSH），并运用Linux的write来互相通信。

8. 配置嵌入式板卡上的SAMBA客户端，使它能访问PC上共享的目录；

9. 尝试各种与嵌入式板卡传递文件的方式并做比较：

10. 通过SAMBA共享；

11. 通过NFS共享（选做）；

12. 通过sftp传递；

13. 通过串口XModem协议传递；

14. 通过Dropbox共享（选做）。

15. 选择和安装PC上的交叉编译环境；

16. 交叉编译C语言的浮点运算程序到pcDuino上去运行，证明所编译的程序是ARM的；

17. 尝试嵌入式板卡上的三个语言的开发环境：C/C++、Python和Java；

18. 尝试一种从PC远程访问嵌入式板卡图形桌面的方式：x-window（通过SSH）、RDP或VNC。

三、实验过程和数据记录

1. 安装USB串口欲动和串口终端软件

a. 实验使用的USb串口线芯片为PL2303，从官网下载Mac对应的驱动。

b. 安装串口程序minicom，使用命令brew install minicom安装，minicom –s命令打开串口程序

Figure 1 minicom启动界面

2. 画出你所实际实施的连接示意图；

Figure 2 树莓派通过串口进行连接

3. 给出实际拍摄的板卡连接照片；

Figure 3 板卡连接照片

4. 给出所用的器材的列表；

a. RaspberryPi B+

b. MacOS

c. DVI显示器

d. 无线路由器一台

e. Micro-USB线

f. USB-TTL串口线

g. HDMI-DVI连接线

h. USB键盘

i. 5V电源（充电宝）

5. 给出拷贝得到的树莓派启动时的输出文字，并逐行解释；

Uncompressing Linux... done, booting the kernel. # 解压内核并且启动树莓派

[ 0.000000] Booting Linux on physical CPU 0xf00

# 树莓派启动CPU

[ 0.000000] Initializing cgroup subsys cpu

[ 0.000000] Initializing cgroup subsys cpuacct

# 初始化cgroups子系统

[ 0.000000] Linux version 3.18.7-v7+ (dc4@dc4-XPS13-9333) (gcc version 4.8.3 20140303 (prerelease) (crosstool-NG linaro-1.13.1+bzr2650 - Linaro GCC 2014.03) ) #755 SMP PREEMPT Thu Feb 12 17:20:48 GMT 2015

# Linux内核版本号，以及交叉编译的访问，用户名和工具链等信息

[ 0.000000] CPU: ARMv7 Processor [410fc075] revision 5 (ARMv7), cr=10c5387d

# CPU型号：ARMv7

[ 0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache

# 指令和cache类型

[ 0.000000] Machine model: Raspberry Pi 2 Model B

# 树莓派型号：2代B

[ 0.000000] cma: Reserved 8 MiB at 0x3a800000

[ 0.000000] Memory policy: Data cache writealloc

# 数据cache策略为fetch on write

[ 0.000000] [bcm2709_smp_init_cpus] enter (8620->f3003010)

[ 0.000000] [bcm2709_smp_init_cpus] ncores=4

# CPU为4核

[ 0.000000] PERCPU: Embedded 11 pages/cpu @ba05d000 s12864 r8192 d24000 u45056

[ 0.000000] Built 1 zonelists in Zone order, mobility grouping on. Total pages: 239776

[ 0.000000] Kernel command line: dma.dmachans=0x7f35 bcm2708_fb.fbwidth=592 bcm2708_fb.fbheight=448 bcm2709.boardrev=0xa21041 bcm2709.serial=0x3951248f smsc95xx.macaddr=B8:27:EB:51:24:8F bcm2708_fb.fbswap=1 bcm2709.disk_led_gpio=47 bcm2709.disk_led_active_low=0 sdhci-bcm2708.emmc_clock_freq=250000000 vc_mem.mem_base=0x3dc00000 vc_mem.mem_size=0x3f000000 dwc_otg.lpm_enable=0 console=ttyAMA0,115200 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline rootwait

# 内核启动的某些参数，包括CPU、内存以及各个终端

[ 0.000000] PID hash table entries: 4096 (order: 2, 16384 bytes)

[ 0.000000] Dentry cache hash table entries: 131072 (order: 7, 524288 bytes)

[ 0.000000] Inode-cache hash table entries: 65536 (order: 6, 262144 bytes)

# 内核进程、文件缓存哈洗表

[ 0.000000] Memory: 940740K/966656K available (5785K kernel code, 377K rwdata, 1760K rodata, 396K init, 771K bss, 25916K reserved)

# 占用内存报告

[ 0.000000] Virtual kernel memory layout:

[ 0.000000] vector : 0xffff0000 - 0xffff1000 ( 4 kB)

[ 0.000000] fixmap : 0xffc00000 - 0xffe00000 (2048 kB)

[ 0.000000] vmalloc : 0xbb800000 - 0xff000000 (1080 MB)

[ 0.000000] lowmem : 0x80000000 - 0xbb000000 ( 944 MB)

[ 0.000000] modules : 0x7f000000 - 0x80000000 ( 16 MB)

[ 0.000000] .text : 0x80008000 - 0x80766748 (7546 kB)

[ 0.000000] .init : 0x80767000 - 0x807ca000 ( 396 kB)

[ 0.000000] .data : 0x807ca000 - 0x808287ec ( 378 kB)

[ 0.000000] .bss : 0x808287ec - 0x808e96d4 ( 772 kB)

# 内段地址分配

[ 0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1

[ 0.000000] Preemptible hierarchical RCU implementation.

[ 0.000000] NR_IRQS:480

[ 0.000000] Architected cp15 timer(s) running at 19.20MHz (virt).

# ARM的cp15处理器，管理cache等

[ 0.000015] sched_clock: 56 bits at 19MHz, resolution 52ns, wraps every 3579139424256ns

[ 0.000039] Switching to timer-based delay loop, resolution 52ns

[ 0.000340] Console: colour dummy device 80x30

[ 0.001767] console [tty1] enabled

[ 0.001818] Calibrating delay loop (skipped), value calculated using timer frequency.. 38.40 BogoMIPS (lpj=192000)

[ 0.001901] pid_max: default: 32768 minimum: 301

[ 0.002319] Mount-cache hash table entries: 2048 (order: 1, 8192 bytes)

[ 0.002380] Mountpoint-cache hash table entries: 2048 (order: 1, 8192 bytes)

[ 0.003661] Initializing cgroup subsys memory

[ 0.003747] Initializing cgroup subsys devices

[ 0.003806] Initializing cgroup subsys freezer

[ 0.003856] Initializing cgroup subsys net_cls

[ 0.003920] Initializing cgroup subsys blkio

# 初始化cgroups子系统，内存以及块设备等

[ 0.004033] CPU: Testing write buffer coherency: ok

[ 0.004151] ftrace: allocating 19969 entries in 59 pages

[ 0.053552] CPU0: update cpu_capacity 1024

[ 0.053633] CPU0: thread -1, cpu 0, socket 15, mpidr 80000f00

[ 0.053670] [bcm2709_smp_prepare_cpus] enter

[ 0.053838] Setting up static identity map for 0x536c78 - 0x536cd0

[ 0.113528] [bcm2709_boot_secondary] cpu:1 started (0) 17

[ 0.113843] CPU1: Booted secondary processor

[ 0.113851] [bcm2709_secondary_init] enter cpu:1

[ 0.113906] CPU1: update cpu_capacity 1024

[ 0.113915] CPU1: thread -1, cpu 1, socket 15, mpidr 80000f01

[ 0.133488] [bcm2709_boot_secondary] cpu:2 started (0) 18

[ 0.133738] CPU2: Booted secondary processor

[ 0.133745] [bcm2709_secondary_init] enter cpu:2

[ 0.133775] CPU2: update cpu_capacity 1024

[ 0.133784] CPU2: thread -1, cpu 2, socket 15, mpidr 80000f02

[ 0.153550] [bcm2709_boot_secondary] cpu:3 started (0) 16

[ 0.153789] CPU3: Booted secondary processor

[ 0.153796] [bcm2709_secondary_init] enter cpu:3

[ 0.153828] CPU3: update cpu_capacity 1024

[ 0.153837] CPU3: thread -1, cpu 3, socket 15, mpidr 80000f03

[ 0.153930] Brought up 4 CPUs

[ 0.154051] SMP: Total of 4 processors activated (153.60 BogoMIPS).

[ 0.154084] CPU: All CPU(s) started in SVC mode.

[ 0.155091] devtmpfs: initialized

[ 0.178144] VFP support v0.3: implementor 41 architecture 2 part 30 variant 7 rev 5

[ 0.180314] pinctrl core: initialized pinctrl subsystem

[ 0.183364] NET: Registered protocol family 16

[ 0.188987] DMA: preallocated 4096 KiB pool for atomic coherent allocations

# DMA初始化

[ 0.213342] cpuidle: using governor ladder

[ 0.243371] cpuidle: using governor menu

[ 0.243767] bcm2709.uart_clock = 3000000

[ 0.246525] No ATAGs?

[ 0.246588] hw-breakpoint: found 5 (+1 reserved) breakpoint and 4 watchpoint registers.

[ 0.246643] hw-breakpoint: maximum watchpoint size is 8 bytes.

[ 0.246706] mailbox: Broadcom VideoCore Mailbox driver

[ 0.246836] bcm2708_vcio: mailbox at f300b880

[ 0.247217] bcm_power: Broadcom power driver

[ 0.247261] bcm_power_open() -> 0

[ 0.247287] bcm_power_request(0, 8)

[ 0.747990] bcm_mailbox_read -> 00000080, 0

[ 0.748022] bcm_power_request -> 0

[ 0.748178] Serial: AMBA PL011 UART driver

[ 0.748340] dev:f1: ttyAMA0 at MMIO 0x3f201000 (irq = 83, base_baud = 0) is a PL011 rev3

[ 1.266655] console [ttyAMA0] enabled

# 串口终端ttyAMA0

[ 1.336774] SCSI subsystem initialized

# SCSI子系统

[ 1.340793] usbcore: registered new interface driver usbfs

[ 1.346457] usbcore: registered new interface driver hub

[ 1.351917] usbcore: registered new device driver usb

[ 1.358863] Switched to clocksource arch_sys_counter

[ 1.393698] FS-Cache: Loaded

[ 1.396947] CacheFiles: Loaded

[ 1.412382] NET: Registered protocol family 2

[ 1.418002] TCP established hash table entries: 8192 (order: 3, 32768 bytes)

[ 1.425254] TCP bind hash table entries: 8192 (order: 4, 65536 bytes)

[ 1.431955] TCP: Hash tables configured (established 8192 bind 8192)

[ 1.438426] TCP: reno registered

[ 1.441708] UDP hash table entries: 512 (order: 2, 16384 bytes)

[ 1.447693] UDP-Lite hash table entries: 512 (order: 2, 16384 bytes)

[ 1.454446] NET: Registered protocol family 1

[ 1.459296] RPC: Registered named UNIX socket transport module.

[ 1.465237] RPC: Registered udp transport module.

[ 1.470025] RPC: Registered tcp transport module.

[ 1.474747] RPC: Registered tcp NFSv4.1 backchannel transport module.

[ 1.482249] bcm2708_dma: DMA manager at f3007000

[ 1.487063] vc-mem: phys_addr:0x00000000 mem_base=0x3dc00000 mem_size:0x3f000000(1008 MiB)

[ 1.497011] futex hash table entries: 1024 (order: 4, 65536 bytes)

[ 1.503477] audit: initializing netlink subsys (disabled)

[ 1.509001] audit: type=2000 audit(1.299:1): initialized

[ 1.530605] VFS: Disk quotas dquot_6.5.2

[ 1.534920] Dquot-cache hash table entries: 1024 (order 0, 4096 bytes)

[ 1.544594] FS-Cache: Netfs 'nfs' registered for caching

[ 1.550974] NFS: Registering the id_resolver key type

[ 1.556100] Key type id_resolver registered

[ 1.560326] Key type id_legacy registered

[ 1.565451] msgmni has been set to 1853

[ 1.571057] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 252)

[ 1.578672] io scheduler noop registered

[ 1.582657] io scheduler deadline registered (default)

[ 1.588132] io scheduler cfq registered

[ 1.594657] BCM2708FB: allocated DMA memory fac00000

[ 1.599719] BCM2708FB: allocated DMA channel 0 @ f3007000

[ 1.611492] Console: switching to colour frame buffer device 74x28

[ 1.623887] bcm2708-dmaengine bcm2708-dmaengine: Load BCM2835 DMA engine driver

[ 1.635022] uart-pl011 dev:f1: no DMA platform data

[ 1.642231] vc-cma: Videocore CMA driver

[ 1.647872] vc-cma: vc_cma_base = 0x00000000

[ 1.654274] vc-cma: vc_cma_size = 0x00000000 (0 MiB)

[ 1.661320] vc-cma: vc_cma_initial = 0x00000000 (0 MiB)

[ 1.680229] brd: module loaded

[ 1.690979] loop: module loaded

[ 1.695996] vchiq: vchiq_init_state: slot_zero = 0xba800000, is_master = 0

[ 1.706752] Loading iSCSI transport class v2.0-870.

[ 1.714236] usbcore: registered new interface driver smsc95xx

[ 1.721721] dwc_otg: version 3.00a 10-AUG-2012 (platform bus)

[ 1.929486] Core Release: 2.80a

[ 1.934234] Setting default values for core params

[ 1.940697] Finished setting default values for core params

[ 2.148293] Using Buffer DMA mode

[ 2.153233] Periodic Transfer Interrupt Enhancement - disabled

[ 2.160749] Multiprocessor Interrupt Enhancement - disabled

[ 2.167992] OTG VER PARAM: 0, OTG VER FLAG: 0

[ 2.174057] Dedicated Tx FIFOs mode

[ 2.179588] WARN::dwc_otg_hcd_init:1047: FIQ DMA bounce buffers: virt = 0xbac14000 dma = 0xfac14000 len=9024

[ 2.192805] FIQ FSM acceleration enabled for :

[ 2.192805] Non-periodic Split Transactions

[ 2.192805] Periodic Split Transactions

[ 2.192805] High-Speed Isochronous Endpoints

[ 2.216097] WARN::hcd_init_fiq:412: FIQ on core 1 at 0x803e4200

[ 2.223755] WARN::hcd_init_fiq:413: FIQ ASM at 0x803e455c length 36

[ 2.231744] WARN::hcd_init_fiq:438: MPHI regs_base at 0xbb806000

[ 2.239521] dwc_otg bcm2708_usb: DWC OTG Controller

[ 2.246149] dwc_otg bcm2708_usb: new USB bus registered, assigned bus number 1

[ 2.256752] dwc_otg bcm2708_usb: irq 32, io mem 0x00000000

[ 2.264022] Init: Port Power? op_state=1

[ 2.269656] Init: Power Port (0)

[ 2.274817] usb usb1: New USB device found, idVendor=1d6b, idProduct=0002

[ 2.284986] usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1

[ 2.295678] usb usb1: Product: DWC OTG Controller

[ 2.302165] usb usb1: Manufacturer: Linux 3.18.7-v7+ dwc_otg_hcd

[ 2.309968] usb usb1: SerialNumber: bcm2708_usb

[ 2.317237] hub 1-0:1.0: USB hub found

[ 2.322850] hub 1-0:1.0: 1 port detected

[ 2.329467] usbcore: registered new interface driver usb-storage

[ 2.337491] mousedev: PS/2 mouse device common for all mice

[ 2.345556] bcm2835-cpufreq: min=600000 max=900000

[ 2.352514] sdhci: Secure Digital Host Controller Interface driver

[ 2.360555] sdhci: Copyright(c) Pierre Ossman

[ 2.366863] DMA channels allocated for the MMC driver

[ 2.408901] Load BCM2835 MMC driver

[ 2.416256] sdhci-pltfm: SDHCI platform and OF driver helper

[ 2.424491] ledtrig-cpu: registered to indicate activity on CPUs

[ 2.435913] hidraw: raw HID events driver (C) Jiri Kosina

[ 2.443444] usbcore: registered new interface driver usbhid

[ 2.451908] usbhid: USB HID core driver

[ 2.460977] TCP: cubic registered

[ 2.467145] Initializing XFRM netlink socket

[ 2.473284] NET: Registered protocol family 17

[ 2.482951] Key type dns_resolver registered

[ 2.489444] Registering SWP/SWPB emulation handler

[ 2.496811] registered taskstats version 1

[ 2.502808] vc-sm: Videocore shared memory driver

[ 2.509144] [vc_sm_connected_init]: start

[ 2.515488] [vc_sm_connected_init]: end - returning 0

[ 2.518839] mmc0: host does not support reading read-only switch, assuming write-enable

[ 2.523156] mmc0: new high speed SDHC card at address aaaa

[ 2.523712] mmcblk0: mmc0:aaaa SU08G 7.40 GiB

[ 2.534894] mmcblk0: p1 p2

[ 2.551240] Indeed it is in host mode hprt0 = 00021501

[ 2.577664] EXT4-fs (mmcblk0p2): INFO: recovery required on readonly filesystem

[ 2.588922] EXT4-fs (mmcblk0p2): write access will be enabled during recovery

[ 2.738998] usb 1-1: new high-speed USB device number 2 using dwc_otg

[ 2.747444] Indeed it is in host mode hprt0 = 00001101

[ 2.949246] usb 1-1: New USB device found, idVendor=0424, idProduct=9514

[ 2.959557] usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0

[ 2.971446] hub 1-1:1.0: USB hub found

[ 2.977247] hub 1-1:1.0: 5 ports detected

[ 3.258999] usb 1-1.1: new high-speed USB device number 3 using dwc_otg

[ 3.379227] usb 1-1.1: New USB device found, idVendor=0424, idProduct=ec00

[ 3.390036] usb 1-1.1: New USB device strings: Mfr=0, Product=0, SerialNumber=0

[ 3.404349] smsc95xx v1.0.4

[ 3.472950] smsc95xx 1-1.1:1.0 eth0: register 'smsc95xx' at usb-bcm2708_usb-1.1, smsc95xx USB 2.0 Ethernet, b8:27:eb:51:24:8f

[ 4.061742] EXT4-fs (mmcblk0p2): orphan cleanup on readonly fs

[ 4.070169] EXT4-fs (mmcblk0p2): 5 orphan inodes deleted

[ 4.077539] EXT4-fs (mmcblk0p2): recovery complete

[ 4.113104] EXT4-fs (mmcblk0p2): mounted filesystem with ordered data mode. Opts: (null)

[ 4.125163] VFS: Mounted root (ext4 filesystem) readonly on device 179:2.

[ 4.137120] devtmpfs: mounted

[ 4.142662] Freeing unused kernel memory: 396K (80767000 - 807ca000)

[ 5.176112] udevd[174]: starting version 175

[ 7.436480] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null)

[ 7.680789] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null)

øø

Raspbian GNU/Linux 7 raspberrypi ttyAMA0

raspberrypi login: pi

Password:

Last login: Thu Nov 26 14:27:29 UTC 2015 on tty1

Linux raspberrypi 3.18.7-v7+ #755 SMP PREEMPT Thu Feb 12 17:20:48 GMT 2015 armv7l

6. 如何通过Linux获得硬件数据，截屏给出获得的硬件数据，如CPU型号、时钟频率、内存大小等；

可以通过cat /proc/cpinfo | grep name | cut –f2 –d: | uniq –c命令查看CPU型号

Figure 4 CPU info

可以使用cpufreq-into命令查看时钟频率

Figure 5 时钟频率信息

可以通过cat /proc/meminfo来查看树莓派内存大小

Figure 6 RAM info

7. 给出你的网络配置参数，截屏给出从pcDuino和PC两端得到的网络已连接的证明；

Figure 7 ifconfig

Figure 8 路由器客户端列表

Figure 9 PC端ping树莓派端

Figure 10 树莓派端ping PC端

8. 给出你的SSH配置文件，并解释其中内容；

以下是SSH配置文件：

# This is the ssh client system-wide configuration file. See

# ssh_config(5) for more information. This file provides defaults for

# users, and the values can be changed in per-user configuration files

# or on the command line.

# Configuration data is parsed as follows:

# 1. command line options

# 2. user-specific file

# 3. system-wide file

# Any configuration value is only changed the first time it is set.

# Thus, host-specific definitions should be at the beginning of the

# configuration file, and defaults at the end.

# Site-wide defaults for some commonly used options. For a comprehensive

# list of available options, their meanings and defaults, please see the

# ssh_config(5) man page.

Host * # 声明只适用于与hostnames相匹配的主机。后面可以加通配符*，表示制定所有主机。

# ForwardAgent no

# ForwardX11 no # 如果设置为yes，那么自动通过一条安全通道以不可信模式来转发X11连接，但是并不设置shell变量DISPLAY。如果ForwardX11Trusted也设置为yes，那么连接以可信模式转发。

# ForwardX11Trusted yes # 与前一配置一同使用时，ForwardX11必须设置为yes。

# RhostsRSAAuthentication no

# RSAAuthentication yes

# PasswordAuthentication yes

# HostbasedAuthentication no

# GSSAPIAuthentication no

# GSSAPIDelegateCredentials no

# GSSAPIKeyExchange no

# GSSAPITrustDNS no

# BatchMode no

# CheckHostIP yes #设置为yes，那么出了用know_hosts文件中的主机名之外，还可以采用IP地址来识别远程系统。如果设置为no则只能使用主机名。

# AddressFamily any

# ConnectTimeout 0

# StrictHostKeyChecking ask # 决定openSSH是否将主机密钥添加到用户的known_hosts文件中以及如何添加。设置为ask则表示在连接新系统时会询问是否添加主机密钥

# IdentityFile ~/.ssh/identity

# IdentityFile ~/.ssh/id_rsa

# IdentityFile ~/.ssh/id_dsa

# Port 22 # 使openSSH通过22号端口与远程系统连接

# Protocol 2,1

# Cipher 3des

# Ciphers aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc

# MACs hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160

# EscapeChar ~

# Tunnel no

# TunnelDevice any:any

# PermitLocalCommand no

# VisualHostKey no

# ProxyCommand ssh -q -W %h:%p gateway.example.com

SendEnv LANG LC_*

HashKnownHosts yes # 当设置为yes时，OpenSSH会将文件~/.ssh/know_hosts中的主机名和地址进行散列。当设置为no时，主机名与地址将以明文形式写入。

GSSAPIAuthentication yes

GSSAPIDelegateCredentials no

9. 存在多个登陆时，如何看到不同端口的登陆，给出截屏结果；

通过三个端口登录（本机外接显示屏、串口和SSH登录），我们可以通过命令w来显示多端口登录的信息。

Figure 11 两个端口的登录信息

Figure 12 三个端口同时登录照片

我们可以使用write命令来完成不同端口之间的通信：

Figure 13 不同端口通过write命令通信

10. 给出嵌入式板卡上的SAMBA配置文件内容，并逐行解释；

以下是SAMBA配置文件内容：

# Sample configuration file for the Samba suite for Debian GNU/Linux.

# This is the main Samba configuration file. You should read the

# smb.conf(5) manual page in order to understand the options listed

# here. Samba has a huge number of configurable options most of which

# are not shown in this example

# Some options that are often worth tuning have been included as

# commented-out examples in this file.

# - When such options are commented with ";", the proposed setting

# differs from the default Samba behaviour

# - When commented with "#", the proposed setting is the default

# behaviour of Samba but the option is considered important

# enough to be mentioned here

# NOTE: Whenever you modify this file you should run the command

# "testparm" to check that you have not made any basic syntactic

# errors.

# A well-established practice is to name the original file

# "smb.conf.master" and create the "real" config file with

# testparm -s smb.conf.master >smb.conf

# This minimizes the size of the really used smb.conf file

# which, according to the Samba Team, impacts performance

# However, use this with caution if your smb.conf file contains nested

# "include" statements. See Debian bug #483187 for a case

# where using a master file is not a good idea.

#======================= Global Settings =======================

# 全局参数

[global]

## Browsing/Identification ###

# Change this to the workgroup/NT-domain name your Samba server will part of

workgroup = WORKGROUP # 设定Samba Server所要加入的工作组或者域

# server string is the equivalent of the NT Description field

server string = %h server # 设定Samba Server的注释，可以是任何字符串，也可以不填

# Windows Internet Name Serving Support Section:

# WINS Support - Tells the NMBD component of Samba to enable its WINS Server

# wins support = no

# WINS Server - Tells the NMBD components of Samba to be a WINS Client

# Note: Samba can be either a WINS Server, or a WINS Client, but NOT both

; wins server = w.x.y.z

# This will prevent nmbd to search for NetBios names through DNS.

dns proxy = no

# What naming service and in what order should we use to resolve host names

# to IP addresses

; name resolve order = lmhosts host wins bcast

#### Networking ####

# The specific set of interfaces / networks to bind to

# This can be either the interface name or an IP address/netmask;

# interface names are normally preferred

; interfaces = 127.0.0.0/8 eth0 # 设置Samba Server监听哪些网卡，可以写网卡名，也可以写该网卡的IP地址

# Only bind to the named interfaces and/or networks; you must use the

# 'interfaces' option above to use this.

# It is recommended that you enable this feature if your Samba machine is

# not protected by a firewall or is a firewall itself. However, this

# option cannot handle dynamic or non-broadcast interfaces correctly.

; bind interfaces only = yes

#### Debugging/Accounting ####

# This tells Samba to use a separate log file for each machine

# that connects

log file = /var/log/samba/log.%m # 设置Samba Server日志文件的存储位置以及日志文件名称。在文件名后加个宏%m（主机名），表示对每台访问Samba Server的机器都单独记录一个日志文件。如果pc1、pc2访问过Samba Server，就会在/var/log/samba目录下留下log.pc1和log.pc2两个日志文件。

# Cap the size of the individual log files (in KiB).

max log size = 1000 # 设置Samba Server日志文件的最大容量，单位为kB，0代表不限制。

# If you want Samba to only log through syslog then set the following

# parameter to 'yes'.

# syslog only = no

# We want Samba to log a minimum amount of information to syslog. Everything

# should go to /var/log/samba/log.smbd,nmbd instead. If you want to log

# through syslog you should set the following parameter to something higher.

syslog = 0

# Do something sensible when Samba crashes: mail the admin a backtrace

panic action = /usr/share/samba/panic-action %d

####### Authentication #######

# "security = user" is always a good idea. This will require a Unix account

# in this server for every user accessing the server. See

# /usr/share/doc/samba-doc/htmldocs/Samba3-HOWTO/ServerType.html

# in the samba-doc package for details.

# security = user # 设置用户访问Samba Server的验证方式，user代表Samba Server共享目录只能被授权的用户访问，由Samba Server负责检查账号和密码的正确性。账号和密码要在Samba Server中建立。

# You may wish to use password encryption. See the section on

# 'encrypt passwords' in the smb.conf(5) manpage before enabling.

encrypt passwords = true # 是否将认证密码加密。因为现在windows操作系统都是使用加密密码，所以一般要开启此项。配置文件默认为开启。

# If you are using encrypted passwords, Samba will need to know what

# password database type you are using.

passdb backend = tdbsam

obey pam restrictions = yes

# This boolean parameter controls whether Samba attempts to sync the Unix

# password with the SMB password when the encrypted SMB password in the

# passdb is changed.

unix password sync = yes

# For Unix password sync to work on a Debian GNU/Linux system, the following

# parameters must be set (thanks to Ian Kahan <<kahan@informatik.tu-muenchen.de> for

# sending the correct chat script for the passwd program in Debian Sarge).

passwd program = /usr/bin/passwd %u

passwd chat = *Enter\\snew\\s*\\spassword:* %n\\n *Retype\\snew\\s*\\spassword:* %n\\n *password\\supdated\\ssuccessfully* .

# This boolean controls whether PAM will be used for password changes

# when requested by an SMB client instead of the program listed in

# 'passwd program'. The default is 'no'.

pam password change = yes

# This option controls how unsuccessful authentication attempts are mapped

# to anonymous connections

map to guest = bad user # 该选项表示不成功的验证尝试会被重定向到bad user界面

########## Domains ###########

# Is this machine able to authenticate users. Both PDC and BDC

# must have this setting enabled. If you are the BDC you must

# change the 'domain master' setting to no

; domain logons = yes

# The following setting only takes effect if 'domain logons' is set

# It specifies the location of the user's profile directory

# from the client point of view)

# The following required a [profiles] share to be setup on the

# samba server (see below)

; logon path = \\\\%N\\profiles\\%U

# Another common choice is storing the profile in the user's home directory

# (this is Samba's default)

# logon path = \\\\%N\\%U\\profile

# The following setting only takes effect if 'domain logons' is set

# It specifies the location of a user's home directory (from the client

# point of view)

; logon drive = H:

# logon home = \\\\%N\\%U

# The following setting only takes effect if 'domain logons' is set

# It specifies the script to run during logon. The script must be stored

# in the [netlogon] share

# NOTE: Must be store in 'DOS' file format convention

; logon script = logon.cmd

# This allows Unix users to be created on the domain controller via the SAMR

# RPC pipe. The example command creates a user account with a disabled Unix

# password; please adapt to your needs

; add user script = /usr/sbin/adduser --quiet --disabled-password --gecos "" %u

# This allows machine accounts to be created on the domain controller via the

# SAMR RPC pipe.

# The following assumes a "machines" group exists on the system

; add machine script = /usr/sbin/useradd -g machines -c "%u machine account" -d /var/lib/samba -s /bin/false %u

# This allows Unix groups to be created on the domain controller via the SAMR

# RPC pipe.

; add group script = /usr/sbin/addgroup --force-badname %g

########## Printing ##########

# If you want to automatically load your printer list rather

# than setting them up individually then you'll need this

# load printers = yes

# lpr(ng) printing. You may wish to override the location of the

# printcap file

; printing = bsd

; printcap name = /etc/printcap

# CUPS printing. See also the cupsaddsmb(8) manpage in the

# cupsys-client package.

; printing = cups

; printcap name = cups

############ Misc ############

# Using the following line enables you to customise your configuration

# on a per machine basis. The %m gets replaced with the netbios name

# of the machine that is connecting

; include = /home/samba/etc/smb.conf.%m

# Most people will find that this option gives better performance.

# See smb.conf(5) and /usr/share/doc/samba-doc/htmldocs/Samba3-HOWTO/speed.html

# for details

# You may want to add the following on a Linux system:

# SO_RCVBUF=8192 SO_SNDBUF=8192

# socket options = TCP_NODELAY

# The following parameter is useful only if you have the linpopup package

# installed. The samba maintainer and the linpopup maintainer are

# working to ease installation and configuration of linpopup and samba.

; message command = /bin/sh -c '/usr/bin/linpopup "%f" "%m" %s; rm %s' &

# Domain Master specifies Samba to be the Domain Master Browser. If this

# machine will be configured as a BDC (a secondary logon server), you

# must set this to 'no'; otherwise, the default behavior is recommended.

# domain master = auto

# Some defaults for winbind (make sure you're not using the ranges

# for something else.)

; idmap uid = 10000-20000

; idmap gid = 10000-20000

; template shell = /bin/bash

# The following was the default behaviour in sarge,

# but samba upstream reverted the default because it might induce

# performance issues in large organizations.

# See Debian bug #368251 for some of the consequences of *not*

# having this setting and smb.conf(5) for details.

; winbind enum groups = yes

; winbind enum users = yes

# Setup usershare options to enable non-root users to share folders

# with the net usershare command.

# Maximum number of usershare. 0 (default) means that usershare is disabled.

; usershare max shares = 100 # 最大的分享用户的数目，0表示用户之间不能分享文件

# Allow users who've been granted usershare privileges to create

# public shares, not just authenticated ones

usershare allow guests = yes

#======================= Share Definitions =======================

[homes]

comment = Home Directories # comment是对该共享的描述，可以是任意字符串

browseable = no

# By default, the home directories are exported read-only. Change the

# next parameter to 'no' if you want to be able to write to them.

read only = yes

# File creation mask is set to 0700 for security reasons. If you want to

# create files with group=rw permissions, set next parameter to 0775.

create mask = 0700

# Directory creation mask is set to 0700 for security reasons. If you want to

# create dirs. with group=rw permissions, set next parameter to 0775.

directory mask = 0700

# By default, \\\\server\\username shares can be connected to by anyone

# with access to the samba server.

# The following parameter makes sure that only "username" can connect

# to \\\\server\\username

# This might need tweaking when using external authentication schemes

valid users = %S # 用来指定允许访问该共享资源的用户

# Un-comment the following and create the netlogon directory for Domain Logons

# (you need to configure Samba to act as a domain controller too.)

;[netlogon]

; comment = Network Logon Service

; path = /home/samba/netlogon

; guest ok = yes

; read only = yes

# Un-comment the following and create the profiles directory to store

# users profiles (see the "logon path" option above)

# (you need to configure Samba to act as a domain controller too.)

# The path below should be writable by all users so that their

# profile directory may be created the first time they log on

;[profiles]

; comment = Users profiles

; path = /home/samba/profiles

; guest ok = no

; browseable = no

; create mask = 0600

; directory mask = 0700

[printers]

comment = All Printers

browseable = no

path = /var/spool/samba

printable = yes

guest ok = no

read only = yes

create mask = 0700

# Windows clients look for this share name as a source of downloadable

# printer drivers

[print$]

comment = Printer Drivers

path = /var/lib/samba/printers

browseable = yes

read only = yes

guest ok = no

# Uncomment to allow remote administration of Windows print drivers.

# You may need to replace 'lpadmin' with the name of the group your

# admin users are members of.

# Please note that you also need to set appropriate Unix permissions

# to the drivers directory for these users to have write rights in it

; write list = root, @lpadmin

# A sample share for sharing your CD-ROM with others.

;[cdrom]

; comment = Samba server's CD-ROM

; read only = yes

; locking = no

; path = /cdrom

; guest ok = yes

# The next two parameters show how to auto-mount a CD-ROM when the

# cdrom share is accesed. For this to work /etc/fstab must contain

# an entry like this:

# /dev/scd0 /cdrom iso9660 defaults,noauto,ro,user 0 0

# The CD-ROM gets unmounted automatically after the connection to the

# If you don't want to use auto-mounting/unmounting make sure the CD

# is mounted on /cdrom

; preexec = /bin/mount /cdrom

; postexec = /bin/umount /cdrom

[home]

comment = laowang's data # 对该共享的描述

path = /home # path用来指定共享目录的路径

valid users = pi # 有效的用户

public = no

writable = yes # writable用来指定该共享路径是否可写。

printable = no

create mask = 0777

11. 给出用各种方式传递文件的过程，并从易用性、速度、安全等方面做比较；

SAMBA方式

Mac启动Samba共享服务，需要到“系统偏好设置”中开启

Figure 14 系统设置中共享界面

在树莓派挂载后，便可正常读写，可以看到在树莓派端往Mac新建文件后，Mac就能够正常读取出来

树莓派上需要设置samba服务，编辑/etc/samba/smb.conf文件，在smbpasswd中添加用户名和密码，在Mac端输入smb://IP，即可读写树莓派的目录。

Figure15 Mac端登录树莓派目录

sFTP方式

下面演示在Mac端使用sftp方式向树莓派用户传输文件

使用命令

sftp root@192.168.1.104

root@192.168.1.104’s password

Connected to 192.168.1.104

Figure 16 sftp传输文件

串口XModem方式

为了使用Xmodem协议，Mac上需要安装lrzxz软件包，并建立连接

brew install lrzxz

ln –s lrx rx

ln –s lsx sx

在树莓派端输入sxfilename，并启用minicom菜单接受文件，即可成功传输文件。

Figure 17 使用minicom接收文件

三种传递方式的比较：

1. 就速度而言，samba最快，sftp辞职，xmodem最慢

2. 就传输介质而言，samba最便捷；sftp需要经过加密传输，速度会稍微慢一些，xmodem通过串口线传输数据，要求最高

3. 就安全性而言，通过串口直连，安全性都非常高。要是不通过串口相连，sftp安全性最高，因为通过加密传输。Samba和xmodem方式安全性能较低。

12. 给出你所选择的交叉编译环境的情况：来源、安装过程等

在Github下载编译完成的armGNU工具链，ARMx-2009q3-67.tar.bz2。

由于Mac默认的文件系统不是大小写敏感的，而源于linux的工具链大小写敏感，所以需要使用系统自带的硬盘工具建立空白映像，并将工具链解压于其中。

挂载后设置PATH变量后便可使用

export PATH=$PATH:/Volumes/arm/bin

13. 给出交叉编译的程序的情况，并证明它是ARM/MIPS的可执行文件；

在PC端的C语言文件

经过编译之后，得到a.out文件，通过file命令检测，证明其为arm汇编可执行文件

将其通过scp命令拷贝到树莓派中

通过ssh登录树莓派，验证C语言程序交叉编译

14. 给出嵌入式板卡本机开发环境的情况，给出一或两种语言编程的例子和结果；

C在树莓派上的编译运行

Python在树莓派上的解释运行

Java在树莓派上的编译运行

15. 给出你尝试的远程图形桌面的方式：嵌入式板卡端的配置方法，PC端软件的获得，使用结果截屏等。

嵌入式板卡上直接使用sudo apt-get install tightvncserver安装VNC server。安装完成之后，使用tightvncserver启动VNC服务器，并且创建密码，如下图所示。

Figure 18 VNC server

PC端使用VNC viewer，可以在http://www.realvnc.com/download/get/1246/网址可以下载。

下载完成之后，打开如下界面

Figure 19 VNC Viewer

输入树莓派的IP地址与打开服务器的序号（默认为1），点击connect，之后输入之前在服务器端设置的密码，就可以打开图形化界面，如下图所示：

Figure 20 树莓派图形化桌面

四、实验结果分析

实验结果即操作实现图，展示在第三部分实验过程中，故本部分内容略过。

五、讨论与心得

本次实验难度较大。主要原因是之前对于嵌入式系统接触太少，导致对于配置文件的细节部分掌握的不够，理解出现问题。

通过本次实验，对嵌入式系统有了更深一步的了解，希望在以后的实验中能够越来越熟练的完成实验。

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