Acorn Software

Software Product Description

SQUASH

Squash is real-time data compression software that works exactly like a 
standard OpenVMS disk. Yet, Squash adds up to 750% [reported by 
customers in real applications] more disk capacity to your storage 
systems and is totally compatible with all OpenVMS applications. Squash 
compresses data automatically and continuously. 
Squash disk(s) appear to OpenVMS systems like a locally connected disk - 
all data stored on it is compressed automatically as it is written and 
decompressed as it is read. For speed and performance, Squash has a 
variable sized cache for quick reads; for further flexibility in 
technical and business requirements, compression levels are user-set in 
an easy-to-use menu driven interface. 
  *	Squash disks: speed and integrity 
  *	Squashed by how much? 
  *	Squash in-a-nutshell 
  *	Squash disks 
  *	Backup 
  *	Distribution media/documentation 
  *	Installation and configuration 
  *	Software requirements 
  *	Software licensing and kits 
  *	Software warranty 
  *	Ordering information 
  *	Software product services 
  *	Comparison against the competition 


Squash disks: speed and integrity


Squash safeguards data during compression to ensure data integrity. A 
system crash cannot leave data partially compressed with invalid data 
structures. Here's how the Squash algorithm protects data: whenever data 
is written to a Squash disk, an uncompressed version of the data is 
allocated on disk and recorded there. Once the data is safely compressed 
and recorded, the uncompressed version space is reclaimed. Squash uses 
an internal variable-sized cache for quick data retrival and fast data 
compression. Data written to cache produces an immediate write to a 
Squash disk and data read from a Squash disk is automatically 
decompressed and delivered to the application. User control can be 
excersized over the cache size and algorithms. 
Caching bridges the need for rapid access and rapid searching of the 
cache, while also maintaining peak efficiency for uncompressed format 
temporary storage on disk. 

Squashed by how much?


Object and executable files have compression ratios of 3.2 : 1 Text 
files have compression ratios of 2.2 : 1 Database files have compression 
ratios of 8.6 : 1 
Squash uses disk space only when needed, resulting in large disk 
savings. Already compressed or encrypted data cannot be compressed 
efficiently enough to save at least one disk block and will be stored in 
an uncompressed format. 

Squash in-a-nutshell

  *	True OpenVMS VAX and OpenVMS AXP disk emulation. 
  *	All OpenVMS disk functions: mount, dismount, shadowing, and striping. 
  *	100% compatible with all OpenVMS applications. 
  *	Multiple compression levels for optimum system performance. 
  *	Safety-write feature for data integrity by protecting data while it is 
	being compressed. 
  *	Variable-sized cache for quick access to information. 
  *	Supports OpenVMS backup operations. 
  *	Read-only version for free distribution 
  *	Adds up to 750% more disk capacity without buying more disks. 
  *	Supports hierarchical storage management (HSM) applications such as file 
	migration. 
  *	Reduces capital equipment costs; extends the usage of current equipment. 
  *	Straightforward pricing provides cost-effective savings for VAX and AXP 
	machines. 


Squash disks


Acorn Squash disk appear local to either OpenVMS VAX or OpenVMS AXP: 
they can be used as hosts for other virtual disks, stripsets, 
shadowsets, or volume sets. 
A Squash disk is at least 4096 blocks and grows as more space is needed. 
Squash allocates approximately 2500 blocks of storage (enough to cover 
the cache plus a little working room) and extends the Squash disk-like 
file in 2048-block increments. 

Backup


Backups of virtual disks work like backups of any VMS disk. Squash 
provides the additional option of backing up the compressed data, saving 
space and time. To facilitate data recovery in case of disaster, Acorn 
provides a read-only version of Squash which can be used to read Squash 
disks, but cannot write them. Writes are ignored as though they had 
taken place, but without altering the data. This version can be used 
anywhere and may be distributed freely so that offsite recovery of data 
from backups of compressed disk containers can be carried out. 

Distribution media/documentation


Squash is distributed on 4mm, 8mm, TK50 tape cartidges, optical 
cartidges, FTP, Gopher, and WWW. Documentation, consisting of a user 
guide, is available both on-line and in printed versions. 

Installation and configuration


Squash is provided as a VMSINSTAL kit. Configuring a Squash disk is 
menu-driven and can be done in minutes. To create a Squash disk, select 
the size of the disk, the index file space, the location, the mode of 
compression, and your Squash disk is ready to use. Other options include 
mounting a Squash disk at boot time, adjusting Squash cache size, and 
reporting on Squash disks. 

Software requirements


OpenVMS/VAX version 5.4 or higher. OpenVMS/AXP version 1.0 or higher 

Software licensing and kits


Squash V2.2-2 is available on the internet. Once installed and started, 
Squash is licensed for 45 days. After this 45-day trial period a 
permanent license to use Squash is issued after Acorn Software has 
received payment in full. This software is furnished under the licensing 
provisions of Acorn Software's Standard Terms and Conditions. For more 
information about licensing terms and policies, contact your local 
reseller or Acorn Software, Inc. 

Software warranty


Warranty for this product is provided by Acorn Software, Inc. with the 
purchase of a permanent license for the product. 
Acorn Software offers a Standard Warranty for Squash. Purchase of this 
warranty is recommended and includes the right to new versions of the 
software product and conformance to the application Software Product 
Description (SPD) for one year. 
Squash purchased without the Standard Warranty is limited to a one year 
conformance to application SPD. Acorn Software Inc. will remedy any 
nonconformance reported during the first year of operation. 

ORDERING INFORMATION



Software Licenses: SQL-*-V (OpenVMS VAX)
                   SQL-*-A (OpenVMS AXP)



Software Maintenance: SQM-*-V (OpenVMS VAX)
                      SQM-*-A (OpenVMS AXP)


* denotes variant fields. For additional information on available 
licenses, media, documentation, services, and warranty refer to the 
Squash Price List. 

SOFTWARE PRODUCT SERVICES


A variety of service options are available from Acorn Software. For more 
information, contact your local reseller or Acorn Software, Inc.


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Copyright (c) 1996 Acorn Software, Inc. All rights reserved 
