When you setup system on a fresh disk you may encounter a problem of corrupted GPT backup. This will happen even more likely when you messed with MBR before on that disk. Free and Open GDISK utility will help you. GDISK will tell you current state of the disk and partition tables, also warn you on possible problems. When you print available partitions (‘p’) and they seem okay, you can simply write out (‘w’) the partition table, that would fix the GPT backup corruption problem
If you want to build your own disk array, let’s say RAID, on your computer to increase disk space and efficiency, you should know about few important things in general:
- You can consider MBR and x86 obsolete. New way is GPT, UEFI, AMD64.
- Large RAID arrays (over 2TB) will not work with older hardware and OS (except FreeBSD) due to architecture limitations.
- To use large RAID volumes you must use GPT partition scheme. MBR will not do the job.
- Some systems can use GPT only with UEFI BIOS (i.e. Windows works with GPT only via UEFI). You may be forced to buy new motherboard.
- UEFI and GPT is totally different way of bootstrap so you can forget what you know about BIOS and MBR here.
- Hard Drives have hidden corruption-fix mechanisms in firmware that will make your RAID array fail to operate. For RAID choose dedicated drives such as WD RED (not Green, not Black, not Blue).
In order to use GPT and UEFI I have replaced my nice ASUS M4A88TD-V EVO/USB3 motherboard with M5A97 R2.0 only because M4 series did not support UEFI. New BIOS is totally different, but I am not really sure if replacing the hardware was mandatory..
Summing up, if you want to use large RAID volumes make sure first that you can use GPT and UEFI BIOS is present on your AMD64 hardware. If not, still you can use the FreeBSD as it knows how to bypass some limitations. Also remember to use dedicated HDD for RAID operations.
If you find keyboard/mouse to be missing when installing Windows7 on a new hardware, make sure you are connected to USB2.0 ports not USB3.0. New hardware host of USB3.0 may not yet be supported by older installer software.
In order to create OSX installer on USB memory drive you need to:
- Download the Mac OSX Yosemite installer from AppStore on you Mac.
- Create installation media from Terminal by executing following command (remember to adjust YOURUSBVOLUME value):
sudo /Applications/Install\ OS\ X\ Yosemite.app/Contents/Resources/createinstallmedia --volume /Volumes/YOURUSBVOLUME --applicationpath /Applications/Install\ OS\ X\ Yosemite.app --nointeraction
- Boot target Mac from USB by pressing ALT/OPTION key while powering-on the computer.
- Remember to format target drive first with Disk Utility if you want to perform clean installation.
In case you wonder why your device does not connect as Modem via Bluetooth to the Mac OSX, or you cannot see COM port on Windows, your mobile device may not simply support or provide DUN (Dial Up Network) and/or SPP (Serial Port Profile) profile.
On Mac OSX I got following error, until I tried another device and/or starting by hand DUN service on a mobile/client machine:
cannot open /dev/cu.Bluetooth-Modem: Resource busy
- Read Bluetooth specification for Serial Port Profile.
- Read Bluetooth specification for Dial-Up Network Profile.
- Modern mobile phones / USB 3G dongles, unfortunately, do not provide direct AT/Hayes access to the Radio Modem anymore.
- You can install DUN application for your smartphone, but it will be only a simple dummy wrapper imitating modem for simple applications, but they do not provide full modem functionality, beware, its a fake.
- Its only necessary for devices to be paired first in order to get SPP/DUN working. If device does not provide serial port over bluetooth when devices are paired and online, probably its just not there implemented.
There are situations when you have a nice server out there, and you want/need someone to upload important files, but you only want to give them a minimal access to the system. You can use SSHD with sFTP and /sbin/nologin shell for that in chroot environment (dedicated limited userspace). Note that SCP in fact requires a working shell, so you need to use sFTP in this case..
Create a new user account with existing ftp group and /sbin/nologin shell:
Alternatively you can modify an existing account to share:
# pw groupmod ftp -m username # pw usermod username -s /sbin/nologin
You need to set correct permissions to the user home directory and public directory inside for upload:
# chown root:wheel /home/username # mkdir /home/username/public # chown username:ftp /home/username/public
Now modify the SSHD server configuration file /etc/ssh/sshd_config and append:
Match Group ftp ChrootDirectory /home/%u ForceCommand internal-sftp AllowTcpForwarding no PermitTunnel no X11Forwarding no
Remember to restart the SSHD in order to apply new configuration:
# service sshd restart
Once the account is not necessary anymore remember to remove it:
# pw userdel username
If you want to perform a fresh installation of OSX 10.10 Yosemite on an older MacBook(Pro) you can obtain the installer with AppStore and then create the USB installation media.
In case you encounter an Installer Verification Error that prevents you from installing the new system try the following. Its not the system date not bad download as internets says.
This may also help you when encountering problems (i.e. USB Mass Storage) after system upgrade to Yosemite.
Try these boot keyboard shortcuts until you hear boot sound two times:
- Cmd+Alt+R+P when powering on the Mac (NVRAM Reset)
- Alt+Ctrl+Shift+PowerON alltogether (SMC Reset)
No problem, you are wolcome
I have, finally, switched to Apple OS X. This is so close to my favorite FreeBSD (OSX is a Unix BSD / Darwin derivative) and it has all drivers and multimedia features working, that I think I will switch for good. This the simple, stable, and functional platform, where you can really focus on your work. Along with the MacPorts suite installed that provide access to the Open-Source / Free-Software I feel like home
If you want to use GSM/3G/LTE modem on your FreeBSD box you need to use PPP and following configuration:
default: set log Phase Chat LCP IPCP CCP tun command ident user-ppp VERSION set device /dev/cuaU0 set phone *99\# set redial 5 10 set speed 115200 set dial "ABORT BUSY ABORT NO\\sCARRIER TIMEOUT 5 \ \"\" ATH OK ATZ OK AT OK-AT-OK ATE1Q0 OK \ AT+CFUN=1 OK-AT-OK \ AT+CPIN? READY-AT+CPIN=\"1234\"-OK \ AT+CGDCONT=1,\"ip\",\"internet\" OK \ \\dATDT\\T TIMEOUT 40 CONNECT" set timeout 10 enable dns set ifaddr 10.0.0.1/0 10.0.0.2/0 255.255.255.255 0.0.0.0 add default HISADDR