Distributed Antenna Systems (DAS – distributed antenna system). Configuring DAS for Windows. How does DAS appear?

09/12/2005, Mon, 09:09, Moscow time

In some countries of the world, the state has long obligated companies to store information about all transactions and all correspondence with partners for a long time, which forces enterprises to spend huge sums on corporate systems data storage. There is no such law in Russia yet, but in order to meet the requirements of foreign investors, Russian companies are also forced to spend significant sums on corporate storage. The choice most often centers around three leading technologies.

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SAN vs NAS and DAS

The most promising technologies for building corporate data storage today are SAN (Storage Area Network) storage devices, devices directly connected to DAS (Direct Attached Storage) servers, and NAS (Network Attached Storage) devices connected via the Internet.

Comparative characteristics storage systems

Source: CNews Analytics

DAS - directly to the server

The DAS system is connected directly to the server, which is why it is also called SAS (Server Attached Software). Other servers can only be accessed through the owner's server. An external RAID array is connected to one or more servers via SCSI or FC (Fibre Channel), with each of these ports accessible to only one server. The main advantage of SAS over other options is its low cost and high performance (in the calculation - one data storage system for one server). With relatively low hardware costs, SAS systems are good for storing streaming multimedia data due to high speed exchange with disks, as well as the ability to build capacious systems. SAS is perfect solution for small and medium-sized companies, as well as for individual users.

But traditional data storage, which involves a direct connection to the server, has a number of significant disadvantages. Since SAS uses a local network for data transfer, when connecting several servers with storage systems, the load on local network increases greatly. Therefore, users will not be able to obtain information for a long time. SAS solutions also do not allow multiple servers to share data files. Moreover, they are limited a short distance connecting the server to data storage systems. And yet, today many Russian customers prefer SAS solutions. Since one of the main advantages of this solution is its low cost.

DAS drives can be called a stripped-down analogue of a NAS server, since the device differs from the latter in the need for a direct connection to a computer. That is, before us, in fact, there are several hard drives in one box, and not an independent home cloud. However, this was the case when Direct-attached storage first appeared.

The bare minimum that can be installed

Today, they are often used to expand the storage of the same NAS, and if you have direct hands and a router with support for DAS host devices, it can be turned into a NAS. In addition, such storage is cheaper, has good data transfer speeds (not without USB help 3.0 and eSATA), and also serves as a suitable option for fast and constant backup.

This happens when there is no DAS

At the same time, you should not think that you are getting a simple box for an HDD or SSD with a RAID controller, because DAS, as a rule, has a cooling system and separate power supply, does not require installation of additional software (although it is worth taking care of this for backup) and has a whole scattering of necessary ports. In order not to be unfounded, I will give several examples of optimal DAS drives in different price categories - from budget devices to high-capacity professional models (both external and built-in).

External DAS for everyone

DAS have the advantage of compact dimensions with a larger storage capacity compared to conventional portable boxes with SSD and HDD.  Such devices have the function of hot-swappable hard drives, as well as attractive appearance, organically fitting into both home and work environments. At the same time, some models are equipped with an LCD screen to monitor the status of the storage; they can be freely switched or act as a single array, without requiring tinkering with the BIOS and loading special drivers.

The Taiwanese company Raidon, founded seven years ago, stands out from competitors due to the use in the production of equipment not only of high-quality third-party components, but also of its own controllers. In other words, this is not just an “assembler”, but a developer who is constantly improving proprietary technology. The manufacturer has in its assortment both budget models, and pro-solutions, equally beneficial for their category of users.

A striking example of an inexpensive DAS device is a model with a typical Taiwanese alphanumeric marking - GR3660-B3. The box can accommodate up to two 3.5-inch HDDs and has a special switch on the rear panel that allows you to select one of three operating modes: RAID 0 (shared storage field), RAID 1 (mirroring) or JBOD (two independent disks) storage mode. Thus, the drive can be used as a family library, expand a NAS server with it, or back up, for example, design projects. This is greatly facilitated by the hot-swappable disk function and support for storage capacity up to 8 TB.

The device, built on the proprietary JMS561 chipset, has a six-gigabit SATA, USB 3.0 is used as an external interface, and the maximum throughput equal to 500 MB/s. Among other features - compact body made of steel and plastic, in the depths of which a 40 mm cooler is hidden. The factory fan is low-speed, so it is better to replace it with something more serious a large number blades, fortunately 12-volt external power allows this. There was also a light indication of the work process. Moreover, this is not just a network connection light, but an alarm about access to DAS, operation failure, rebuilding and connection status. The maximum thickness of the disk for installation inside should not exceed 26.1 mm - be sure to pay attention to this before purchasing. Raidon GR3660-B3 weighs 830 g with dimensions 64 x 120 x 220 mm. Worth it (all prices listed are current at the time of publication of the review).

CFI (CFI Group) is another Taiwanese manufacturer, but with a richer history (founded in 1987). The company specializes in the development and sale of multi-disk external drives for various tasks. Interestingly, CFI produces official duplicates of Micron, Silicon Image, Marvell and NEC devices, and also produces equipment commissioned by well-known IT companies. In general, you should not think that you are acquiring a “noname”. Moreover, in terms of price-quality ratio, CFI DAS drives are among the best.

CFI-B4043JDGG based on JMicron JMB394 and JMS539 chipsets – 4-disk RAID storage with eSATA and USB 3.0. It supports 3.5-inch HDD SATA II and most SATA I models, which can operate in Clean, Large, Clone and RAID0,1,10,3,5 modes, that is, act as separate local drives or be a single array . Moreover, the latter can be automatically rebuilt in RAID1,10,3 and RAID5 modes, and maximum speed reaches 200 GB/h.

Other advantages include a built-in power supply that saves space on your desktop, operation indication on the front panel and an attractive design. The housing is made of steel and has cross-ventilation without dust filter. A low-speed, low-noise 80mm cooler is used as an active cooling system. The only (and, in general, insignificant) drawback: to “hot” replace the HDD, you need to remove the outer cover of the case - in this regard, the Raidon GR3660-B3 trays are much more convenient. However, it is hardly possible to find something better.

An excellent example of optimal 4-disk storage is Raidon GR5630-SB3 For this money you get not only a maximum capacity of up to 32 TB (8 TB x 4), USB 3.0 and eSATA, but also convenient trays for hot-swap hard drives, a 200-watt power supply with cooling, aluminum body and simply attractive appearance.

The advantages of the model include automatic rebuilding of the array if one or two drives fail. In this case, not only external, but also internal backup is possible. There is a separate sensor for temperature and for the fan, the readings from which can be read with a certain amount of enthusiasm. Among the shortcomings is the data transfer speed of 300 MB/s, which is not the best indicator for such a price tag, but this is not surprising, because the disk interface is SATA II, 3 GB/s.

However, these little things more than make up for the support RAID levels 0, 1, 5, JBOD and compact body (168 x 125 x 212 mm, weight 4.1 kg).

If you part with a little more money, then you can get a much interesting DAS device with similar RAID modes, manually activated. In addition, the model features two FireWire 800 coupled with USB 3.0 and eSATA.  The number of hot-swappable baskets remains the same, but the HDD interface here is represented by a second-generation six-gigabit SATA, which is a big plus.

There is auto-rebuild of the array, but the main feature is the monochrome LCD display, which displays the entire necessary information. For example, there is an indication of HDD failure, failure of the cooling system (here represented by an 80 mm fan) and overheating.

Other features include a Kensington lock, which physically prevents the device from being stolen, as well as manual shutdown/activation of air cooling. The 200-watt power supply is protected from network sags and overloads. At the same time, DAS has similar dimensions to its younger brother, but weighs a little more - 4.5 kg in a package.

Speaking of external DAS, we should not lose sight of the five-disc models, intended more for the office than for the home (however, geeks are unfamiliar with these frameworks). This is a hardware 2-channel RAID platform based on duplicated RAID controllers, mainly intended for working with archives and large-scale backups. For this purpose, support for RAID levels 0, 3, 5, Basic, JBOD, as well as 4 KB sectors is implemented, and USB 3.0 or eSATA can be used for data transfer.  Due to the fact that the internal interface here is eSATA 3 Gb/s, a speed of 500 MB/s is achieved.

Cooling is indirectly provided by an aluminum case and a 120mm fan. It’s a pity that the display here is mediocre (work and power), although it’s hard to imagine such a giant next to a modest laptop: best company for him - NAS or a sysadmin's refuge.

The rich equipment is also pleasing. So, in addition to the power cable in the box you can find USB 3.0 A-B, eSATA and a HDD mounting kit.  This miracle weighs 6.5 kg with dimensions of 150x340x340 mm. By the way, the model enjoys a certain degree of popularity, so it’s easy to find a review of the CFI B8283JDGG on the Internet.  Costs

Embedded DAS

Optical drives, excluding Blu-ray discs, are becoming a thing of the past, but 5.25- and 3.5-inch bays in desktops remain. No, case developers do not rivet them out of habit. The fact is that currently there is a large amount of embedded equipment that expands the functionality of computers, and DAS storage is no exception. IN in this case The need for external power is eliminated, and the desktop becomes more spacious.

Compact DAS designed to integrate into a 3.5" bay computer case and holds up to two 2.5-inch hard or solid state drives total capacity up to 4 TB.  Both trays provide for hot-swappable disks, which is a godsend for, for example, an SSD. It’s a pity that this thing is connected via three-gigabit SATA II (300 MB/s), but there is support for zero and first level RAID arrays.

Despite its compact dimensions of 25.8 x 101.7 x 147 mm (weight 570 g), there is a fan inside the case, which means you don’t have to bother with a separate coolant. The front panel is painted neutral black, but the body itself is beige, as was previously the case with optical drives, so fans of modding and acrylic side glass will be a little upset by this state of affairs.

Otherwise there are no complaints. A light indication of operation is implemented, there is a temperature and rotation speed sensor for a 30 mm cooler, automatic switching array if one of the disks fails and a proprietary chipset RAIDON SR2045. At the same time it is worth Raidon SR2760-2S-S2+

If the above model is not enough, then it is worth considering Raidon SR2611-2S-S2R. True, in this case you will have to, but it’s worth it, since you get an effective “plug” for two 5.25-inch body bays. It looks stylish, and the picture is complemented by an informative LCD display with blue backlight. However, this is not the main advantage. Among other things, DAS can accommodate up to two 3.5-inch HDD drives with a total capacity of up to 16 TB, which are very convenient to change using “hot” baskets. A 60mm fan acts as a CO.

The connection is made via RS232 or SATA II, 3.0 Gbit/s, power supply is via two 4-pin Molex connectors directly to the desktop power supply, which removes the load from motherboard. The device is built on the RAIDON SR2045 chipset, supports disk redistribution and weighs 2 kg with dimensions of 146 x 85 x 202 mm. Each basket has a lock to prevent unauthorized access. Used for diagnostics and backup special utility RAID GUIDE for Windows platforms. In a word, for this money you get a good foundation for the future.

Welcome to the site dedicated to HP storage systems!
This is the first blog post on the site. In it I will talk about the classification of data storage systems used in modern computer systems.
All data storage systems are divided into three large groups: DAS, NAS and SAN.
Let's look at each group in detail.

DAS— Direct Attached Storage is a solution when the storage device is connected directly to the server or workstation without using a storage network. The literal translation of “Direct Attached Storage” means “directly connected storage.” To connect, an HBA (Host Bus Adapter) is used - a device installed or built into a server or workstation.
The protocols used to connect DAS are ATA, SATA, eSATA, SCSI, SAS, and Fiber Channel.

NAS— Network-attached storage is a data storage system that provides clients with file access and is connected to the network. Network-attached storage is translated as “storage connected to the network.” NAS can be used not only as a file server, but its software and hardware components are specially selected and tested to fulfill the role file server. Clients typically connect to the server via Ethernet network public use. NAS systems typically contain one or more hard drives, often organized into logical, redundant storage groups or RAID arrays. NAS network device data storage relieves responsibility for the safety and access of files from other servers on the network. File access is usually provided through network protocols such as NFS (Network File System), SMB/CIFS (Server Message Block/Common Internet File System), or AFP (Apple Filing Protocol).

SAN— Storage area network is a dedicated network that provides access to consolidated, block-based data storage systems. Storage area network is translated as “data storage network”. SANs are mainly used to make storage devices such as disk arrays, tape libraries made available to servers as if they were attached directly to the servers. Typically a SAN is a network of storage devices that are not accessible over the network shared network LAN Since 2000, the cost and complexity of storage networks have decreased to a level that allows widespread adoption even by small and medium-sized companies.
SAN provides no abstraction, only block operations. This means that access to the storage system via NFS, SMB/CIFS, or AFP protocols is possible only through a special gateway server.

Detection system for gradual deterioration in vehicle control DAS VOLVO

Component placement

Note: The DACU is common to all driver warning systems. New DACU unit

design and is similar to the previous yaw rate sensor unit, the hardware has been updated and software. Yaw rate sensor unit (consisting of sensor and power supply)built into the DACU unit.

Attention: The LKS video camera and control unit are common to the DAS and LKS systems.

1. The A60, LKS control unit and video processor are located on the radio shelf.

2. The LKS system camera is connected directly to the A60 and is located in the middle of the windshield.

3. A26, DACU control unit and gateway are located in the rear junction boxelectrical equipment.

4. A03, instrument unit.

Meanings of terms

• ACC Adaptive Cruise Control
• CAN Controller Local Area Network
• DACU Driver assistance system control unit.
• DAS Driver warning system.
• LCM Light control unit
• LKS Lane Keeping Assist
• LCS Lane Change System.
• MID Message identification description
• VECU Vehicle control unit

DAS system, design and principle of operation

The Driver Alert System (DAS) is designed to recognize gradual deterioration

control the car and warn the driver when the car deviates sharply from the lane

movements. The DAS system issues a warning as follows: the sound of the radio is muted, the instrument unit sounds an audible signal and a warning message appears. The driver mustpress the ESC button to confirm the message on the display so that it disappears. Operation of the DAS systemdepends on the clarity of the road markings. If road markings are missing or covered with snow, the system DAS is not working.

Attention: The DAS system only affects the operation of the radio and cruise control system (CC/ACC). To workThe brakes and steering system are not affected.

1. The DAS system is always activated when the ignition is turned on, but it can be disabled on the instrument panel block.
2. The LKS system video camera continuously transmits data to the A60 control unit of this system.
3. The LKS system video camera control unit is a video processor that interpretsimages and transmitting data to the DACU unit.
4. The DACU unit processes data received from the LKS system video camera and the VECU and LCM units. BlockThe DACU continuously transmits DAS system status data to the instrument unit. DACU unitdetermines when it is necessary to warn the driver.
5. If the conditions for issuing a warning are met, the sound of the radio is muted (usingmute function) and at the same time a sound signal is turned on on the instrument unit anda warning message appears.
6. There are two types of warning: weak and strong. When a strong warning is issuedThe DAS system disables the cruise control (CC/ACC) function if it is activated and temporarilyprevents slowdown.

Attention: The driver must press the ESC button to confirm the message for it to disappear.

The warning is valid for a limited time. Sound signal when a warning is issued

is played only once.

7. The LKS system video camera exchanges data via its own J1939–6 channel of the CAN network.
8. Channel J1939–1 of the CAN data bus is used to exchange data with other systems.
9. Programming of the DAS system is done using the VCADS application. Calibration andProgramming of the LKS system video camera is carried out using the VCADS application.diagnostic channel J1587. Fault codes can be read usingVolvo's TECHTOOL applications.

DACU, gateway

Note: The DACU is common to all driver warning systems. Angle sensor blockYaw rate sensor (consisting of sensor and power supply) is built into the DACU.

The DACU control unit and gateway represent the interface of the DAS and LKS systems for communication with other

car systems. The DACU unit stores the DAS warning algorithm.

The DACU unit reads the signal from the LKS system video camera and processes it according to this algorithm And

continuously transmits data on the status of the DAS system to the instrument unit. If the conditions for warning, the DACU issues a warning and a command to activate the shutdown function sound.

The DACU gateway transmits the signal required by the DAS and LKS systems from the CAN communication channel J1939–1 to its own channel J1939–6 and back.

The DACU unit issues test commands to the DAS and LKS systems. Test commands are used for calibration

video cameras of the LKS system and radar of the ACC system.

The DACU has its own fault codes and processes all fault codes for systems DAS and LKS. The DACU responds to the MID number of the DAS and LKS systems via diagnostic channel J1587.

1. When the DAS system is enabled, the DACU side requires data from other control units.

Caution: If this data or signals are missing or incorrect, the DAS system becomes

inactive.

2. Travel speed (via VECU). Brake pedal status (via VECU).

3. Status of direction indicators and presence of an attached trailer (via the LCM).

4. The DACU receives yaw rate data from its built-in sensor.

5. The LKS system video camera control unit is a video processor that interprets information received from the video camera and the DACU unit. This information is processed into a block

DACU returns information such as distance on the left, distance on the right, coefficient

reliability, road markings on the left and road markings on the right.

6. The DACU unit processes this information, determining the state of the DAS system and, in the event

If necessary, a warning is issued and the mute function is activated. DAS system

issues a warning when the driver warning level is low and the following are performed

• There are no fault codes recorded by the system.
• The system is turned on and active.
• The driving speed exceeds 65 km/h (activation speed).
• Attention: When a strong warning is issued, the DAS system disables

Attention: If a strong warning is issued, the DAS system disables the functioncruise control (CC/ACC), if enabled, and temporarily prevents deceleration.

Attention: The DAS function is deactivated if the driving speed drops below 60 km/h (speed

to turn off).

7. In the Favorites menu, the driver can select whether the status should be displayed on the instrument cluster

DAS systems. When DAS is turned off, no indicators are displayed.

Function, angular velocity yaw

The yaw rate sensor is used to determine vehicle turns (the sensor is built into the unit DACU). The yaw rate signal is required for the operation of the DAS system. This signal comes fromthe system's own sensor.

Caution: DAS is inactive if the yaw rate signal is faulty or missing.

1. DACU unit – gateway, yaw rate.
2. ACC control unit and radar
3. Control unit and video camera of the LKS system.
4. LCS radar.

DAS system, indicators

ContentsI. Definition of DAS.
II. Distributed antenna system.
2.1. General scheme DAS network infrastructure and its types.
2.2. Passive RAS.
2.3. Active RAS.
2.4. Stages of RAS design.
2.5. Preparing a radio plan.
III. Technical description RAS components
3.1. RAS control rack
3.2. Connection diagram of the BTS to the MA rack
3.3. Radio remote modules.
3.4. Optical components.
3.5. Antennas indoor.
3.6. Coaxial RF cable.
3.7. Splitters symmetrical/asymmetrical.
3.8. Radio frequency jumpers.
3.9. Measurements of radio parameters of the constructed indoor network.

I. Definition of DAS

II. Distributed Antenna System

2.1 General diagram of the DAS network infrastructure and its types.

2.2 Passive distributed antenna system.

2.3 Active distributed antenna system.

2.3.1 Active distributed antenna system.

2.4 Stages of RAS design.

10. 2.5 Radio plan preparation stage.

11.III. Technical description of RAS

12. 3.1 Distributed antenna system control rack.

13. 3.2 Connection diagram of the operator’s BS to the control rack.

14. 3.3 Remote radio modules

15. 3.4 Optical components

16. 3.4.1 Optical components

17. 3.5 Antennas used in indoor solutions

18. 3.6 RF coaxial cable/connector.

19. 3.7 Symmetrical and asymmetrical splitters.

20. 3.8 RF connecting jumper

21. 3.9 Measurements of the constructed indoor network.

22.