KR100392611B1 - Scsi backplane board - Google Patents

Abstract

The present invention relates to a small computer system interface (SCSI) backplane board, comprising a general control of the SCSI backplane board, an EPLD (SCID) register, disk ID select, and device power control. Erasable Programmable Logic Device, which is controlled by the EPLD logic section, transfers 8-bit asynchronous SCSI data, provides a master / slave I ² C bus, device slot status, power supply status, fan SCSI Accessed Fault-Tolerant Enclosures (SAF-TE) logic section for controlling status, temperature status, and SCSI bus operating mode, and under the control of the EPLD logic section, SCSI-1, 2, and 3, fast SCSI, Supports Ultra, Ultra2, Ultra3, provides active termination for 9 signal line pairs, provides multi-mode low voltage differential / single end (LVD / SE) termination, and automatically selects LVD or SE termination Ha Includes a terminator logic unit.

Description

Small Computer System Interface Backplane Board {SCSI BACKPLANE BOARD}

The present invention relates to a small computer system interface (SCSI), and more particularly to a SCSI backplane board.

SCSI is evolving into the ANSI standard, an electronic interface that allows PCs and peripherals such as disk drives, tape drives, CD-ROM drives, printers, scanners, and more to communicate faster and more flexibly than previous interfaces. Current SCSI sets are parallel interfaces, and SCSI ports are present in most PCs today and are supported by almost all major operating systems.

In addition to fast data rates, SCSI is more flexible than previous parallel data transfer interfaces. The latest SCSI standard, Ultra-2 SCSI for 16-bit Buses, can transfer data up to 80 Mbps. Although SCSI depends on the width of the bus, you can have seven to 15 peripherals connected in a row to one SCSI port. This approach is considered an ideal interface for portable computers such as laptops because a single circuit board or card is sufficient instead of having a separate card for each device to accommodate all the peripherals. One host adapter in the form of a PC card can support a SCSI interface for one laptop, freeing the use of a parallel port with a printer and a serial port with an external modem while other devices are in use.

The original SCSI, now called SCSI-1, has evolved to SCSI-2, which is now widely supported. SCSI-3 consists of a set of basic commands and an additional, specialized set of commands tailored to the needs of a particular device type. The suite of SCSI-3 command sets is used for additional parallel and serial protocols as well as SCSI-3 parallel interfaces.

A widely adopted SCSI standard is Ultra-2, which uses a 40 MHz clock rate to deliver up to 80 Mbps. This allows the cable distance to be extended up to 12 m by using low voltage differential signaling (LVD) schemes. Early versions of SCSI used a single cable terminated with ground at the end. Ultra-2 SCSI signals data over two cables, represented by different voltages between the two cables, allowing longer cables to be supported. Low voltage differential lowers power consumption and manufacturing costs.

The latest SCSI standard is Ultra-3, which increases the maximum speed from 80 Mbps to 160 Mbps by allowing it to operate with clock speeds. This standard is sometimes called Ultra 160 / m. New disk drives with support for Ultra160 / m will provide faster data transfer rates. The Ultra160 / m also includes domain verification for testing CRC and SCSI networks to ensure the integrity of transmitted data.

1 is a block diagram of a conventional SCSI backplane board. Referring to FIG. 1, the conventional SCSI backplane board supported Ultra and Ultra-2 and did not support Ultra-3. In addition, the SCSI backplane board did not support SCSI Accessed Fault-Tolerant Enclosures (SAF-TE), which prevented automatic hot-swap during RAID configuration. RAID (RAID) is mainly used for servers that have important data, and when multiple hard disks are used, the same data is stored in different locations. Hot-swap is the replacement of hard drives, CD-ROM drives, power supplies, and other such devices while the computer system is running. The replacement of the device may be for the replacement of a failed device, or for other data in the case of a storage device. Hot-swap is accomplished by providing a rack or enclosure that provides external appearance to the bus or I / O controller of the computer, even while the device is removed and replaced by another device.

However, although the conventional SCSI backplane board supports hot-swap in such a RAID configuration, it is inconvenient to use because it is a menual method, and hot-spare is not supported. Hot-spare refers to providing additional standby storage units to keep the system operational at any time and to reduce the chance of fatal data loss. These hot-spare units are physically connected to the system to reconstruct and store the data on the failed unit.

Accordingly, the present invention provides SAF-TE functionality, SSB4 (SAF-TE SCSI Backplane) capable of supporting Wide Ultra-3 LVD SCSI, Wide Ultra-2, and Ultra-SE, and capable of mounting up to four disks. It aims to provide.

In addition, an object of the present invention is to provide a SSB4 having a hot-swap function, which enables the disk to be mounted and detached even when the power is turned on, and the hot-spare function is also implemented.

1 is a block diagram of a conventional SCSI backplane board,

2 is a block diagram of a SAB-TE SCSI Backplane (SSB4) board according to an embodiment of the present invention;

3 is a diagram illustrating operation of device power control logic according to an embodiment of the present invention;

4 is a block diagram of a logic of the SAF-TE (SCSI Accessed Fault-Tolerant Enclosures) logic according to an embodiment of the present invention,

5 is a block diagram of the terminator logic according to an embodiment of the present invention.

In order to achieve the above object, the present invention relates to a small computer system interface (SCSI) backplane board, which generally controls the SCSI backplane board, and includes a SCSI ID register, a disk ID select, and a device. Erasable Programmable Logic Device (EPLD) logic unit for power control, controlled by the EPLD logic unit, transfers 8-bit asynchronous SCSI data, provides master / slave I ² C bus, device slot status, power supply SCSI Accessed Fault-Tolerant Enclosures (SAF-TE) logic section for controlling status, fan status, temperature status, and SCSI bus operating mode, and under the control of the EPLD logic section, SCSI-1, 2, and 3, Supports fast SCSI, Ultra, Ultra2, and Ultra3, provides active termination for 9 signal line pairs, provides multi-mode low voltage differential / single end (LVD / SE) termination, and LVD Or it comprises a terminator (terminator) logic unit for automatically selecting the SE termination.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description and the annexed drawings, detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

2 is a block diagram of a SSB4 (SAF-TE SCSI Backplane) board according to an embodiment of the present invention. Referring to FIG. 2, a block of an SSB4 board according to the present invention is largely composed of an erasable programmable logic device (EPLD) logic unit, a SAF-TE logic unit, and a terminator logic unit.

The EPLD logic section controls the board overall, including SAF-TE logic and terminator logic. The EPLD logic unit performs a GEM354 SCSI ID register, disk ID select, and device power control. Hereinafter, each operation of the EPLD logic unit will be described in detail.

First, the GEM354 SCSI register function will be described. According to the present invention, the EPLD logic unit reads the GEM354 SCSI ID as shown in Table 1 below.

CPU_STRBn PROM_WE LED [3: 0] D [7; 0] Operation Chip 0 One 0 ID SLOT 2, ID SLOT 1 GEM354 0 One One ID SLOT 4, ID SLOT 3 GEM354

Discussing the disk ID selection function, the SSB4 according to the present invention selects the disk ID using a jumper line, so that many devices can be connected to one SCSI bus. In other words, the disk ID is selected using 4 bits. Accordingly, SSB4 selects various disk IDs using SCSI ID 3 and SCSI ID 2 and can be represented as shown in Table 2.

SCSIID 3 SCSIID2 IDSEL3 IDSEL2 0 0 One One One 0 0 One 0 One One 0 One One 0 0

Device power control will be described with reference to FIG. 3. 3 illustrates the operation of device power control logic in accordance with an embodiment of the present invention. SSB4 according to the present invention is initially configured to apply power to each of the disks sequentially in the system without being overloaded at a moment when power is applied to the system. Device power control is implemented so that power can be sequentially applied when a disk is installed using a 23-bit count. The EPLD logic unit waits when the count value COUNT_END = 0 in each state, and proceeds to the next state when the count value COUNT_END = 1. Referring to FIG. 3, in the S6 state, the initial value and the latched value are compared to proceed to each state.

Hereinafter, with reference to FIG. 4, SCSI Accessed Fault-Tolerant Enclosures (SAF-TE) logic will be described. 4 is a block diagram of SAF-TE logic according to an embodiment of the present invention. GEM354 (Enclosure Management Controller) of "Q-Logic" is a chip supporting SAF-TE, and the present invention uses the chip. These GEM354 chips provide 8-bit, asynchronous SCSI data transfer, master / slave I ² C buses, and device status (drive presence, slot address, predicted fault, fault requested, swap, identify, prepare for removal / insertion of operation, unconfigured), power supply (presence, failure), fan (presence, failure), temperature (presence, value, failure), SCSI bus operating modes (single-ended, LVD, HVD) To control.

Next, FIG. 5 is a block diagram of the terminator logic (Terminator Logic) of the SSB4 terminator logic according to an embodiment of the present invention. Terminator in the present invention is to support both LVD / SE using the "Dallas" DS2119M Ultra3 LVD / SE SCSI terminator. This terminator logic supports SCSI-1, 2, and 3, fast SCSI, Ultra, Ultra2, Ultra3, provides active termination for 9 signal line pairs, and multimode low voltage differential Provides Low Voltage Differential / Single Ended (LVD / SE) termination and automatically selects LVD or SE termination.

As described above, the difference between the SSB4 configured according to the embodiment of the present invention and the conventional SCSI backplane board can be shown in Table 3 below.

division Conventional SCSI Backplane SSB4 SCSI bus length 12 meters 12 meters SCSI bus device Four Four Ultra3 SCSI Supported Not supported support SAF-TE Not supported support Hot-swap manual Automatic

As described above, the SSB4 according to the present invention can support Wide Ultra3 SCSI, automatically support a hot-swap function in various configurations when configuring an internal RAID, and also support a hot-spare function.

Meanwhile, in the above description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be defined by the described embodiments, but by the claims and equivalents of the claims.

As described above, according to the present invention, SSF4 (SAF-TE SCSI) capable of supporting SAF-TE function, Wide Ultra-3 LVD SCSI, Wide Ultra-2, and Ultra-SE, and capable of mounting up to four disks Backplane) board can be provided. In addition, the present invention provides a SSB4 board having a hot-swap function, which allows the disk to be mounted and detached even when the power is on, and also implements the hot-spare function.

Claims (1)

In the Small Computer System Interface (SCSI) backplane board, Erasable Programmable Logic Device (EPLD) logic unit that controls the SCSI backplane board as a whole, and performs SCSI ID register, disk ID select, and device power control; Under the control of the EPLD logic section, transfer 8-bit asynchronous SCSI data, provide master / slave I ² C bus, device slot status, power supply status, fan status, temperature status, SCSI bus operating mode And a SCSI Accessed Fault-Tolerant Enclosures (SAF-TE) logic section for controlling the Under the control of the EPLD logic section, it supports SCSI-1, 2, and 3, fast SCSI, Ultra, Ultra2, Ultra3, provides active termination for 9 signal line pairs, and A SCSI backplane board that provides mode low-voltage differential / single-ended (LVD / SE) termination and includes terminator logic to automatically select LVD or SE termination.